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Chromium

February 08, 2023

This article is about the chemical element. For other uses, see Chromium (disambiguation).

Chromium is a chemical element with the symbol Cr and atomic number 24. It is the first element in group 6. It is a steely-grey, lustrous, hard, and brittle transition metal.[4]

Chromium, 24Cr
Chromium
Appearancesilvery metallic
Standard atomic weight Ar°(Cr)
  • 51.9961±0.0006
  • 51.996±0.001 (abridged)[1]
Chromium in the periodic table
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson
–
↑
Cr
↓
Mo
vanadium ← chromium → manganese
Atomic number (Z)24
Groupgroup 6
Periodperiod 4
Block  d-block
Electron configuration[Ar] 3d5 4s1
Electrons per shell2, 8, 13, 1
Physical properties
Phase at STPsolid
Melting point2180 K ​(1907 °C, ​3465 °F)
Boiling point2944 K ​(2671 °C, ​4840 °F)
Density (near r.t.)7.15 g/cm3
when liquid (at m.p.)6.3 g/cm3
Heat of fusion21.0 kJ/mol
Heat of vaporization347 kJ/mol
Molar heat capacity23.35 J/(mol·K)
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 1656 1807 1991 2223 2530 2942
Atomic properties
Oxidation states−4, −2, −1, 0, +1, +2, +3, +4, +5, +6 (depending on the oxidation state, an acidic, basic, or amphoteric oxide)
ElectronegativityPauling scale: 1.66
Ionization energies
  • 1st: 652.9 kJ/mol
  • 2nd: 1590.6 kJ/mol
  • 3rd: 2987 kJ/mol
  • (more)
Atomic radiusempirical: 128 pm
Covalent radius139±5 pm
Spectral lines of chromium
Other properties
Natural occurrenceprimordial
Crystal structure ​body-centered cubic (bcc)
Speed of sound thin rod5940 m/s (at 20 °C)
Thermal expansion4.9 µm/(m⋅K) (at 25 °C)
Thermal conductivity93.9 W/(m⋅K)
Electrical resistivity125 nΩ⋅m (at 20 °C)
Magnetic orderingantiferromagnetic (rather: SDW)[2]
Molar magnetic susceptibility+280.0×10−6 cm3/mol (273 K)[3]
Young's modulus279 GPa
Shear modulus115 GPa
Bulk modulus160 GPa
Poisson ratio0.21
Mohs hardness8.5
Vickers hardness1060 MPa
Brinell hardness687–6500 MPa
CAS Number7440-47-3
History
Discovery and first isolationLouis Nicolas Vauquelin (1794, 1797)
Main isotopes of chromium
Iso­tope Decay
abun­dance half-life (t1/2) mode pro­duct
50Cr 4.345% stable
51Cr syn 27.7025 d ε 51V
γ –
52Cr 83.789% stable
53Cr 9.501% stable
54Cr 2.365% stable
 Category: Chromium
| references

Chromium metal is valued for its high corrosion resistance and hardness. A major development in steel production was the discovery that steel could be made highly resistant to corrosion and discoloration by adding metallic chromium to form stainless steel. Stainless steel and chrome plating (electroplating with chromium) together comprise 85% of the commercial use. Chromium is also greatly valued as a metal that is able to be highly polished while resisting tarnishing. Polished chromium reflects almost 70% of the visible spectrum, and almost 90% of infrared light.[5] The name of the element is derived from the Greek word χρῶμα, chrōma, meaning color,[6] because many chromium compounds are intensely colored.

Industrial production of chromium proceeds from chromite ore (mostly FeCr2O4) to produce ferrochromium, an iron-chromium alloy, by means of aluminothermic or silicothermic reactions. Ferrochromium is then used to produce alloys such as stainless steel. Pure chromium metal is produced by a different process: roasting and leaching of chromite to separate it from iron, followed by reduction with carbon and then aluminium.

In the United States, trivalent chromium (Cr(III)) ion is considered an essential nutrient in humans for insulin, sugar, and lipid metabolism.[7] However, in 2014, the European Food Safety Authority, acting for the European Union, concluded that there was insufficient evidence for chromium to be recognized as essential.[8]

While chromium metal and Cr(III) ions are considered non-toxic, hexavalent chromium, Cr(VI), is toxic and carcinogenic. According to the European Chemicals Agency (ECHA), chromium trioxide that is used in industrial electroplating processes is a "substance of very high concern" (SVHC).[9]

Abandoned chromium production sites often require environmental cleanup.[10]

Physical properties

Atomic

Chromium is the fourth transition metal found on the periodic table, and has an electron configuration of [Ar] 3d5 4s1. It is also the first element in the periodic table whose ground-state electron configuration violates the Aufbau principle. This occurs again later in the periodic table with other elements and their electron configurations, such as copper, niobium, and molybdenum.[11] This occurs because electrons in the same orbital repel each other due to their like charges. In the previous elements, the energetic cost of promoting an electron to the next higher energy level is too great to compensate for that released by lessening inter-electronic repulsion. However, in the 3d transition metals, the energy gap between the 3d and the next-higher 4s subshell is very small, and because the 3d subshell is more compact than the 4s subshell, inter-electron repulsion is smaller between 4s electrons than between 3d electrons. This lowers the energetic cost of promotion and increases the energy released by it, so that the promotion becomes energetically feasible and one or even two electrons are always promoted to the 4s subshell. (Similar promotions happen for every transition metal atom but one, palladium.)[12]

Chromium is the first element in the 3d series where the 3d electrons start to sink into the nucleus; they thus contribute less to metallic bonding, and hence the melting and boiling points and the enthalpy of atomisation of chromium are lower than those of the preceding element vanadium. Chromium(VI) is a strong oxidising agent in contrast to the molybdenum(VI) and tungsten(VI) oxides.[13]

Bulk

 
Sample of pure chromium metal

Chromium is extremely hard, and is the third hardest element behind carbon (diamond) and boron. Its Mohs hardness is 8.5, which means that it can scratch samples of quartz and topaz, but can be scratched by corundum. Chromium is highly resistant to tarnishing, which makes it useful as a metal that preserves its outermost layer from corroding, unlike other metals such as copper, magnesium, and aluminium.

Chromium has a melting point of 1907 °C (3465 °F), which is relatively low compared to the majority of transition metals. However, it still has the second highest melting point out of all the Period 4 elements, being topped by vanadium by 3 °C (5 °F) at 1910 °C (3470 °F). The boiling point of 2671 °C (4840 °F), however, is comparatively lower, having the fourth lowest boiling point out of the Period 4 transition metals alone behind copper, manganese and zinc.[note 1] The electrical resistivity of chromium at 20 °C is 125 nanoohm-meters.

Chromium has a high specular reflection in comparison to other transition metals. In infrared, at 425 μm, chromium has a maximum reflectance of about 72%, reducing to a minimum of 62% at 750 μm before rising again to 90% at 4000 μm.[5] When chromium is used in stainless steel alloys and polished, the specular reflection decreases with the inclusion of additional metals, yet is still high in comparison with other alloys. Between 40% and 60% of the visible spectrum is reflected from polished stainless steel.[5] The explanation on why chromium displays such a high turnout of reflected photon waves in general, especially the 90% in infrared, can be attributed to chromium's magnetic properties.[14] Chromium has unique magnetic properties - chromium is the only elemental solid that shows antiferromagnetic ordering at room temperature and below. Above 38 °C, its magnetic ordering becomes paramagnetic.[2] The antiferromagnetic properties, which cause the chromium atoms to temporarily ionize and bond with themselves, are present because the body-centric cubic's magnetic properties are disproportionate to the lattice periodicity. This is due to the magnetic moments at the cube's corners and the unequal, but antiparallel, cube centers.[14] From here, the frequency-dependent relative permittivity of chromium, deriving from Maxwell's equations and chromium's antiferromagnetism, leaves chromium with a high infrared and visible light reflectance.[15]

Passivation

Chromium metal left standing in air is passivated - it forms a thin, protective, surface layer of oxide. This layer has a spinel structure a few atomic layers thick; it is very dense and inhibits the diffusion of oxygen into the underlying metal. In contrast, iron forms a more porous oxide through which oxygen can migrate, causing continued rusting.[16] Passivation can be enhanced by short contact with oxidizing acids like nitric acid. Passivated chromium is stable against acids. Passivation can be removed with a strong reducing agent that destroys the protective oxide layer on the metal. Chromium metal treated in this way readily dissolves in weak acids.[17]

Chromium, unlike iron and nickel, does not suffer from hydrogen embrittlement. However, it does suffer from nitrogen embrittlement, reacting with nitrogen from air and forming brittle nitrides at the high temperatures necessary to work the metal parts.[18]

Isotopes

Main article: Isotopes of chromium

Naturally occurring chromium is composed of four stable isotopes; 50Cr, 52Cr, 53Cr and 54Cr, with 52Cr being the most abundant (83.789% natural abundance). 50Cr is observationally stable, as it is theoretically capable of decaying to 50Ti via double electron capture with a half-life of no less than 1.3×1018 years. Twenty-five radioisotopes have been characterized, ranging from 42Cr to 70Cr; the most stable radioisotope is 51Cr with a half-life of 27.7 days. All of the remaining radioactive isotopes have half-lives that are less than 24 hours and the majority less than 1 minute. Chromium also has two metastable nuclear isomers.[19]

53Cr is the radiogenic decay product of 53Mn (half-life 3.74 million years).[20] Chromium isotopes are typically collocated (and compounded) with manganese isotopes. This circumstance is useful in isotope geology. Manganese-chromium isotope ratios reinforce the evidence from 26Al and 107Pd concerning the early history of the Solar System. Variations in 53Cr/52Cr and Mn/Cr ratios from several meteorites indicate an initial 53Mn/55Mn ratio that suggests Mn-Cr isotopic composition must result from in-situ decay of 53Mn in differentiated planetary bodies. Hence 53Cr provides additional evidence for nucleosynthetic processes immediately before coalescence of the Solar System.[21]

The isotopes of chromium range in atomic mass from 43 u (43Cr) to 67 u (67Cr). The primary decay mode before the most abundant stable isotope, 52Cr, is electron capture and the primary mode after is beta decay.[19] 53Cr has been posited as a proxy for atmospheric oxygen concentration.[22]

Chemistry and compounds

See also: Category:Chromium compounds
 
The Pourbaix diagram for chromium in pure water, perchloric acid, or sodium hydroxide[23][24]

Chromium is a member of group 6, of the transition metals. The +3 and +6 states occur most commonly within chromium compounds, followed by +2; charges of +1, +4 and +5 for chromium are rare, but do nevertheless occasionally exist.[25][26]

Common oxidation states

Oxidation
states[note 2][26]
−4 (d10) Na4[Cr(CO)4][27]
−2 (d8) Na
2[Cr(CO)
5]
−1 (d7) Na
2[Cr
2(CO)
10]
0 (d6) Cr(C
6H
6)
2
+1 (d5) K
3[Cr(CN)
5NO]
+2 (d4) CrCl
2
+3 (d3) CrCl
3
+4 (d2) K
2CrF
6
+5 (d1) K
3Cr(O
2)
4
+6 (d0) K
2CrO
4

Chromium(0)

Many Cr(0) complexes are known. Bis(benzene)chromium and chromium hexacarbonyl are highlights in organochromium chemistry.

Chromium(II)

Chromium(II) compounds are uncommon, in part because they readily oxidize to chromium(III) derivatives in air. Water-stable chromium(II) chloride CrCl
2 that can be made by reducing chromium(III) chloride with zinc. The resulting bright blue solution created from dissolving chromium(II) chloride is stable at neutral pH.[17] Some other notable chromium(II) compounds include chromium(II) oxide CrO, and chromium(II) sulfate CrSO
4. Many chromium(II) carboxylates are known. The red chromium(II) acetate (Cr2(O2CCH3)4) is somewhat famous. It features a Cr-Cr quadruple bond.[28]

Chromium(III)

 
Anhydrous chromium(III) chloride (CrCl3)

A large number of chromium(III) compounds are known, such as chromium(III) nitrate, chromium(III) acetate, and chromium(III) oxide.[29] Chromium(III) can be obtained by dissolving elemental chromium in acids like hydrochloric acid or sulfuric acid, but it can also be formed through the reduction of chromium(VI) by cytochrome c7.[30] The Cr3+
 ion has a similar radius (63 pm) to Al3+
 (radius 50 pm), and they can replace each other in some compounds, such as in chrome alum and alum.

Chromium(III) tends to form octahedral complexes. Commercially available chromium(III) chloride hydrate is the dark green complex [CrCl2(H2O)4]Cl. Closely related compounds are the pale green [CrCl(H2O)5]Cl2 and violet [Cr(H2O)6]Cl3. If anhydrous violet[31] chromium(III) chloride is dissolved in water, the violet solution turns green after some time as the chloride in the inner coordination sphere is replaced by water. This kind of reaction is also observed with solutions of chrome alum and other water-soluble chromium(III) salts. A tetrahedral coordination of chromium(III) has been reported for the Cr-centered Keggin anion [α-CrW12O40]5–.[32]

Chromium(III) hydroxide (Cr(OH)3) is amphoteric, dissolving in acidic solutions to form [Cr(H2O)6]3+, and in basic solutions to form [Cr(OH)
6]3−
. It is dehydrated by heating to form the green chromium(III) oxide (Cr2O3), a stable oxide with a crystal structure identical to that of corundum.[17]

Chromium(VI)

Main article: Hexavalent chromium

Chromium(VI) compounds are oxidants at low or neutral pH. Chromate anions (CrO2−
4) and dichromate (Cr2O72−) anions are the principal ions at this oxidation state. They exist at an equilibrium, determined by pH:

2 [CrO4]2− + 2 H+ ⇌ [Cr2O7]2− + H2O

Chromium(VI) oxyhalides are known also and include chromyl fluoride (CrO2F2) and chromyl chloride (CrO
2Cl
2).[17] However, despite several erroneous claims, chromium hexafluoride (as well as all higher hexahalides) remains unknown, as of 2020.[33]

 
Chromium(VI) oxide

Sodium chromate is produced industrially by the oxidative roasting of chromite ore with sodium carbonate. The change in equilibrium is visible by a change from yellow (chromate) to orange (dichromate), such as when an acid is added to a neutral solution of potassium chromate. At yet lower pH values, further condensation to more complex oxyanions of chromium is possible.

Both the chromate and dichromate anions are strong oxidizing reagents at low pH:[17]

Cr
2O2−
7 + 14 H
3O+
 + 6 e− → 2 Cr3+
 + 21 H
2O (ε0 = 1.33 V)

They are, however, only moderately oxidizing at high pH:[17]

CrO2−
4 + 4 H
2O + 3 e− → Cr(OH)
3 + 5 OH−
 (ε0 = −0.13 V)
 
Sodium chromate (Na2CrO4)

Chromium(VI) compounds in solution can be detected by adding an acidic hydrogen peroxide solution. The unstable dark blue chromium(VI) peroxide (CrO5) is formed, which can be stabilized as an ether adduct CrO
5·OR
2.[17]

Chromic acid has the hypothetical formula H
2CrO
4. It is a vaguely described chemical, despite many well-defined chromates and dichromates being known. The dark red chromium(VI) oxide CrO
3, the acid anhydride of chromic acid, is sold industrially as "chromic acid".[17] It can be produced by mixing sulfuric acid with dichromate and is a strong oxidizing agent.

Other oxidation states

See also: Organochromium chemistry

Compounds of chromium(V) are rather rare; the oxidation state +5 is only realized in few compounds but are intermediates in many reactions involving oxidations by chromate. The only binary compound is the volatile chromium(V) fluoride (CrF5). This red solid has a melting point of 30 °C and a boiling point of 117 °C. It can be prepared by treating chromium metal with fluorine at 400 °C and 200 bar pressure. The peroxochromate(V) is another example of the +5 oxidation state. Potassium peroxochromate (K3[Cr(O2)4]) is made by reacting potassium chromate with hydrogen peroxide at low temperatures. This red brown compound is stable at room temperature but decomposes spontaneously at 150–170 °C.[34]

Compounds of chromium(IV) are slightly more common than those of chromium(V). The tetrahalides, CrF4, CrCl4, and CrBr4, can be produced by treating the trihalides (CrX
3) with the corresponding halogen at elevated temperatures. Such compounds are susceptible to disproportionation reactions and are not stable in water. Organic compounds containing Cr(IV) state such as chromium tetra t-butoxide are also known.[35]

Most chromium(I) compounds are obtained solely by oxidation of electron-rich, octahedral chromium(0) complexes. Other chromium(I) complexes contain cyclopentadienyl ligands. As verified by X-ray diffraction, a Cr-Cr quintuple bond (length 183.51(4)  pm) has also been described.[36] Extremely bulky monodentate ligands stabilize this compound by shielding the quintuple bond from further reactions.

 
Chromium compound determined experimentally to contain a Cr-Cr quintuple bond

Occurrence

See also: Category:Chromium minerals
 
Crocoite (PbCrO4)
 
Chromite ore

Chromium is the 21st[37] most abundant element in Earth's crust with an average concentration of 100 ppm. Chromium compounds are found in the environment from the erosion of chromium-containing rocks, and can be redistributed by volcanic eruptions. Typical background concentrations of chromium in environmental media are: atmosphere <10 ng/m3; soil <500 mg/kg; vegetation <0.5 mg/kg; freshwater <10 μg/L; seawater <1 μg/L; sediment <80 mg/kg.[38] Chromium is mined as chromite (FeCr2O4) ore.[39]

About two-fifths of the chromite ores and concentrates in the world are produced in South Africa, about a third in Kazakhstan,[40] while India, Russia, and Turkey are also substantial producers. Untapped chromite deposits are plentiful, but geographically concentrated in Kazakhstan and southern Africa.[41] Although rare, deposits of native chromium exist.[42][43] The Udachnaya Pipe in Russia produces samples of the native metal. This mine is a kimberlite pipe, rich in diamonds, and the reducing environment helped produce both elemental chromium and diamonds.[44]

The relation between Cr(III) and Cr(VI) strongly depends on pH and oxidative properties of the location. In most cases, Cr(III) is the dominating species,[23] but in some areas, the ground water can contain up to 39 µg/L of total chromium, of which 30 µg/L is Cr(VI).[45]

History

Early applications

Chromium minerals as pigments came to the attention of the west in the eighteenth century. On 26 July 1761, Johann Gottlob Lehmann found an orange-red mineral in the Beryozovskoye mines in the Ural Mountains which he named Siberian red lead.[46][47] Though misidentified as a lead compound with selenium and iron components, the mineral was in fact crocoite with a formula of PbCrO4.[48] In 1770, Peter Simon Pallas visited the same site as Lehmann and found a red lead mineral that was discovered to possess useful properties as a pigment in paints. After Pallas, the use of Siberian red lead as a paint pigment began to develop rapidly throughout the region.[49] Crocoite would be the principal source of chromium in pigments until the discovery of chromite many years later.[50]

 
The red color of rubies is due to trace amounts of chromium within the corundum.

In 1794, Louis Nicolas Vauquelin received samples of crocoite ore. He produced chromium trioxide (CrO3) by mixing crocoite with hydrochloric acid.[48] In 1797, Vauquelin discovered that he could isolate metallic chromium by heating the oxide in a charcoal oven, for which he is credited as the one who truly discovered the element.[51][52] Vauquelin was also able to detect traces of chromium in precious gemstones, such as ruby and emerald.[48][53]

During the nineteenth century, chromium was primarily used not only as a component of paints, but in tanning salts as well. For quite some time, the crocoite found in Russia was the main source for such tanning materials. In 1827, a larger chromite deposit was discovered near Baltimore, United States, which quickly met the demand for tanning salts much more adequately than the crocoite that had been used previously.[54] This made the United States the largest producer of chromium products until the year 1848, when larger deposits of chromite were uncovered near the city of Bursa, Turkey.[39] With the development of metallurgy and chemical industries in the Western world, the need for chromium increased.[55]

Chromium is also famous for its reflective, metallic luster when polished. It is used as a protective and decorative coating on car parts, plumbing fixtures, furniture parts and many other items, usually applied by electroplating. Chromium was used for electroplating as early as 1848, but this use only became widespread with the development of an improved process in 1924.[56]

Production

 
Piece of chromium produced with aluminothermic reaction
 
World production trend of chromium
 
Chromium, remelted in a horizontal arc zone-refiner, showing large visible crystal grains

Approximately 28.8 million metric tons (Mt) of marketable chromite ore was produced in 2013, and converted into 7.5 Mt of ferrochromium.[41] According to John F. Papp, writing for the USGS, "Ferrochromium is the leading end use of chromite ore, [and] stainless steel is the leading end use of ferrochromium."[41]

The largest producers of chromium ore in 2013 have been South Africa (48%), Kazakhstan (13%), Turkey (11%), and India (10%), with several other countries producing the rest of about 18% of the world production.[41]

The two main products of chromium ore refining are ferrochromium and metallic chromium. For those products the ore smelter process differs considerably. For the production of ferrochromium, the chromite ore (FeCr2O4) is reduced in large scale in electric arc furnace or in smaller smelters with either aluminium or silicon in an aluminothermic reaction.[57]

 
Chromium ore output in 2002[58]

For the production of pure chromium, the iron must be separated from the chromium in a two step roasting and leaching process. The chromite ore is heated with a mixture of calcium carbonate and sodium carbonate in the presence of air. The chromium is oxidized to the hexavalent form, while the iron forms the stable Fe2O3. The subsequent leaching at higher elevated temperatures dissolves the chromates and leaves the insoluble iron oxide. The chromate is converted by sulfuric acid into the dichromate.[57]

4 FeCr2O4 + 8 Na2CO3 + 7 O2 → 8 Na2CrO4 + 2 Fe2O3 + 8 CO2
2 Na2CrO4 + H2SO4 → Na2Cr2O7 + Na2SO4 + H2O

The dichromate is converted to the chromium(III) oxide by reduction with carbon and then reduced in an aluminothermic reaction to chromium.[57]

Na2Cr2O7 + 2 C → Cr2O3 + Na2CO3 + CO
Cr2O3 + 2 Al → Al2O3 + 2 Cr

Applications

The creation of metal alloys account for 85% of the available chromium's usage. The remainder of chromium is used in the chemical, refractory, and foundry industries.[59]

Metallurgy

 
Stainless steel cutlery made from Cromargan 18/10, containing 18% chromium
Main articles: Chrome plating and Stainless steel

The strengthening effect of forming stable metal carbides at grain boundaries, and the strong increase in corrosion resistance made chromium an important alloying material for steel. High-speed tool steels contain between 3 and 5% chromium. Stainless steel, the primary corrosion-resistant metal alloy, is formed when chromium is introduced to iron in concentrations above 11%.[60] For stainless steel's formation, ferrochromium is added to the molten iron. Also, nickel-based alloys have increased strength due to the formation of discrete, stable, metal, carbide particles at the grain boundaries. For example, Inconel 718 contains 18.6% chromium. Because of the excellent high-temperature properties of these nickel superalloys, they are used in jet engines and gas turbines in lieu of common structural materials.[61] ASTM B163 relies on Chromium for condenser and heat-exchanger tubes, while castings with high strength at elevated temperatures that contain Chromium are standardised with ASTM A567.[62] AISI type 332 is used where high temperature would normally cause carburization, oxidation or corrosion.[63] Incoloy 800 "is capable of remaining stable and maintaining its austenitic structure even after long time exposures to high temperatures".[64] Nichrome is used as resistance wire for heating elements in things like toasters and space heaters. These uses make chromium a strategic material. Consequently, during World War II, U.S. road engineers were instructed to avoid chromium in yellow road paint, as it "may become a critical material during the emergency."[65] The United States likewise considered chromium "essential for the German war industry" and made intense diplomatic efforts to keep it out of the hands of Nazi Germany.[66]

 
Decorative chrome plating on a motorcycle

The high hardness and corrosion resistance of unalloyed chromium makes it a reliable metal for surface coating; it is still the most popular metal for sheet coating, with its above-average durability, compared to other coating metals.[67] A layer of chromium is deposited on pretreated metallic surfaces by electroplating techniques. There are two deposition methods: thin, and thick. Thin deposition involves a layer of chromium below 1 µm thickness deposited by chrome plating, and is used for decorative surfaces. Thicker chromium layers are deposited if wear-resistant surfaces are needed. Both methods use acidic chromate or dichromate solutions. To prevent the energy-consuming change in oxidation state, the use of chromium(III) sulfate is under development; for most applications of chromium, the previously established process is used.[56]

In the chromate conversion coating process, the strong oxidative properties of chromates are used to deposit a protective oxide layer on metals like aluminium, zinc, and cadmium. This passivation and the self-healing properties of the chromate stored in the chromate conversion coating, which is able to migrate to local defects, are the benefits of this coating method.[68] Because of environmental and health regulations on chromates, alternative coating methods are under development.[69]

Chromic acid anodizing (or Type I anodizing) of aluminium is another electrochemical process that does not lead to the deposition of chromium, but uses chromic acid as an electrolyte in the solution. During anodization, an oxide layer is formed on the aluminium. The use of chromic acid, instead of the normally used sulfuric acid, leads to a slight difference of these oxide layers.[70] The high toxicity of Cr(VI) compounds, used in the established chromium electroplating process, and the strengthening of safety and environmental regulations demand a search for substitutes for chromium, or at least a change to less toxic chromium(III) compounds.[56]

Pigment

The mineral crocoite (which is also lead chromate PbCrO4) was used as a yellow pigment shortly after its discovery. After a synthesis method became available starting from the more abundant chromite, chrome yellow was, together with cadmium yellow, one of the most used yellow pigments. The pigment does not photodegrade, but it tends to darken due to the formation of chromium(III) oxide. It has a strong color, and was used for school buses in the United States and for the postal services (for example, the Deutsche Post) in Europe. The use of chrome yellow has since declined due to environmental and safety concerns and was replaced by organic pigments or other alternatives that are free from lead and chromium. Other pigments that are based around chromium are, for example, the deep shade of red pigment chrome red, which is simply lead chromate with lead(II) hydroxide (PbCrO4·Pb(OH)2). A very important chromate pigment, which was used widely in metal primer formulations, was zinc chromate, now replaced by zinc phosphate. A wash primer was formulated to replace the dangerous practice of pre-treating aluminium aircraft bodies with a phosphoric acid solution. This used zinc tetroxychromate dispersed in a solution of polyvinyl butyral. An 8% solution of phosphoric acid in solvent was added just before application. It was found that an easily oxidized alcohol was an essential ingredient. A thin layer of about 10–15 µm was applied, which turned from yellow to dark green when it was cured. There is still a question as to the correct mechanism. Chrome green is a mixture of Prussian blue and chrome yellow, while the chrome oxide green is chromium(III) oxide.[71]

Chromium oxides are also used as a green pigment in the field of glassmaking and also as a glaze for ceramics.[72] Green chromium oxide is extremely lightfast and as such is used in cladding coatings. It is also the main ingredient in infrared reflecting paints, used by the armed forces to paint vehicles and to give them the same infrared reflectance as green leaves.[73]

Other uses

 
Red crystal of a ruby laser

Chromium(III) ions present in corundum crystals (aluminium oxide) cause them to be colored red; when corundum appears as such, it is known as a ruby. If the corundum is lacking in chromium(III) ions, it is known as a sapphire.[note 3] A red-colored artificial ruby may also be achieved by doping chromium(III) into artificial corundum crystals, thus making chromium a requirement for making synthetic rubies.[note 4][74] Such a synthetic ruby crystal was the basis for the first laser, produced in 1960, which relied on stimulated emission of light from the chromium atoms in such a crystal. Ruby has a laser transition at 694.3 nanometers, in a deep red color.[75]

Because of their toxicity, chromium(VI) salts are used for the preservation of wood. For example, chromated copper arsenate (CCA) is used in timber treatment to protect wood from decay fungi, wood-attacking insects, including termites, and marine borers.[76] The formulations contain chromium based on the oxide CrO3 between 35.3% and 65.5%. In the United States, 65,300 metric tons of CCA solution were used in 1996.[76]

Chromium(III) salts, especially chrome alum and chromium(III) sulfate, are used in the tanning of leather. The chromium(III) stabilizes the leather by cross linking the collagen fibers.[77] Chromium tanned leather can contain between 4 and 5% of chromium, which is tightly bound to the proteins.[39] Although the form of chromium used for tanning is not the toxic hexavalent variety, there remains interest in management of chromium in the tanning industry. Recovery and reuse, direct/indirect recycling,[78] and "chrome-less" or "chrome-free" tanning are practiced to better manage chromium usage.[79]

The high heat resistivity and high melting point makes chromite and chromium(III) oxide a material for high temperature refractory applications, like blast furnaces, cement kilns, molds for the firing of bricks and as foundry sands for the casting of metals. In these applications, the refractory materials are made from mixtures of chromite and magnesite. The use is declining because of the environmental regulations due to the possibility of the formation of chromium(VI).[57] [80]

Several chromium compounds are used as catalysts for processing hydrocarbons. For example, the Phillips catalyst, prepared from chromium oxides, is used for the production of about half the world's polyethylene.[81] Fe-Cr mixed oxides are employed as high-temperature catalysts for the water gas shift reaction.[82][83] Copper chromite is a useful hydrogenation catalyst.[84]

Chromates of metals are used in humistor.[85]

Uses of compounds

Biological role

See also: Chromium in glucose metabolism

The biologically beneficial effects of chromium(III) are debated.[94][95] Chromium is accepted by the U.S. National Institutes of Health as a trace element for its roles in the action of insulin, a hormone that mediates the metabolism and storage of carbohydrate, fat, and protein.[7] The mechanism of its actions in the body, however, have not been defined, leaving in question the essentiality of chromium.[96][97]

In contrast, hexavalent chromium (Cr(VI) or Cr6+) is highly toxic and mutagenic.[98] Ingestion of chromium(VI) in water has been linked to stomach tumors, and it may also cause allergic contact dermatitis (ACD).[99]

"Chromium deficiency", involving a lack of Cr(III) in the body, or perhaps some complex of it, such as glucose tolerance factor, is controversial.[7] Some studies suggest that the biologically active form of chromium (III) is transported in the body via an oligopeptide called low-molecular-weight chromium-binding substance (LMWCr), which might play a role in the insulin signaling pathway.[100]

The chromium content of common foods is generally low (1-13 micrograms per serving).[7][101] The chromium content of food varies widely, due to differences in soil mineral content, growing season, plant cultivar, and contamination during processing.[101] Chromium (and nickel) leach into food cooked in stainless steel, with the effect being largest when the cookware is new. Acidic foods that are cooked for many hours also exacerbate this effect.[102][103]

Dietary recommendations

See also: Chromium deficiency

There is disagreement on chromium's status as an essential nutrient. Governmental departments from Australia, New Zealand, India, Japan, and the United States consider chromium essential[104][105][106][107] while the European Food Safety Authority (EFSA) of the European Union does not.[108]

The U.S. National Academy of Medicine (NAM) updated the Estimated Average Requirements (EARs) and the Recommended Dietary Allowances (RDAs) for chromium in 2001. For chromium, there was insufficient information to set EARs and RDAs, so its needs are described as estimates for Adequate Intakes (AIs). The current AIs of chromium for women ages 14 through 50 is 25 μg/day, and the AIs for women ages 50 and above is 20 μg/day. The AIs for women who are pregnant are 30 μg/day, and for women who are lactating, the set AIs are 45 μg/day. The AIs for men ages 14 through 50 are 35 μg/day, and the AIs for men ages 50 and above are 30 μg/day. For children ages 1 through 13, the AIs increase with age from 0.2 μg/day up to 25 μg/day. As for safety, the NAM sets Tolerable Upper Intake Levels (ULs) for vitamins and minerals when the evidence is sufficient. In the case of chromium, there is not yet enough information, hence no UL has been established. Collectively, the EARs, RDAs, AIs, and ULs are the parameters for the nutrition recommendation system known as Dietary Reference Intake (DRI).[107] Australia and New Zealand consider chromium to be an essential nutrient, with an AI of 35 μg/day for men, 25 μg/day for women, 30 μg/day for women who are pregnant, and 45 μg/day for women who are lactating. A UL has not been set due to the lack of sufficient data.[104] India considers chromium to be an essential nutrient, with an adult recommended intake of 33 μg/day.[105] Japan also considers chromium to be an essential nutrient, with an AI of 10 μg/day for adults, including women who are pregnant or lactating. A UL has not been set.[106] The EFSA of the European Union however, does not consider chromium to be an essential nutrient; chromium is the only mineral for which the United States and the European Union disagree.[108][109]

Labeling

For U.S. food and dietary supplement labeling purposes, the amount of the substance in a serving is expressed as a percent of the Daily Value (%DV). For chromium labeling purposes, 100% of the Daily Value was 120 μg. As of May 27, 2016, the percentage of daily value was revised to 35 μg to bring the chromium intake into a consensus with the official Recommended Dietary Allowance.[110][111] A table of the old and new adult daily values is provided at Reference Daily Intake.

Food sources

Food composition databases such as those maintained by the U.S. Department of Agriculture do not contain information on the chromium content of foods.[112] A wide variety of animal and vegetable foods contain chromium.[107] Content per serving is influenced by the chromium content of the soil in which the plants are grown, by foodstuffs fed to animals, and by processing methods, as chromium is leached into foods if processed or cooked in stainless steel equipment.[113] One diet analysis study conducted in Mexico reported an average daily chromium intake of 30 micrograms.[114] An estimated 31% of adults in the United States consume multi-vitamin/mineral dietary supplements,[115] which often contain 25 to 60 micrograms of chromium.

Supplementation

Chromium is an ingredient in total parenteral nutrition (TPN), because deficiency can occur after months of intravenous feeding with chromium-free TPN.[116] It is also added to nutritional products for preterm infants.[117] Although the mechanism of action in biological roles for chromium is unclear, in the United States chromium-containing products are sold as non-prescription dietary supplements in amounts ranging from 50 to 1,000 μg. Lower amounts of chromium are also often incorporated into multi-vitamin/mineral supplements consumed by an estimated 31% of adults in the United States.[115] Chemical compounds used in dietary supplements include chromium chloride, chromium citrate, chromium(III) picolinate, chromium(III) polynicotinate, and other chemical compositions.[7] The benefit of supplements has not been proven.[7][118]

Approved and disapproved health claims

In 2005, the U.S. Food and Drug Administration had approved a qualified health claim for chromium picolinate with a requirement for very specific label wording: "One small study suggests that chromium picolinate may reduce the risk of insulin resistance, and therefore possibly may reduce the risk of type 2 diabetes. FDA concludes, however, that the existence of such a relationship between chromium picolinate and either insulin resistance or type 2 diabetes is highly uncertain." At the same time, in answer to other parts of the petition, the FDA rejected claims for chromium picolinate and cardiovascular disease, retinopathy or kidney disease caused by abnormally high blood sugar levels.[119] In 2010, chromium(III) picolinate was approved by Health Canada to be used in dietary supplements. Approved labeling statements include: a factor in the maintenance of good health, provides support for healthy glucose metabolism, helps the body to metabolize carbohydrates and helps the body to metabolize fats.[120] The European Food Safety Authority (EFSA) approved claims in 2010 that chromium contributed to normal macronutrient metabolism and maintenance of normal blood glucose concentration, but rejected claims for maintenance or achievement of a normal body weight, or reduction of tiredness or fatigue.[121]

Given the evidence for chromium deficiency causing problems with glucose management in the context of intravenous nutrition products formulated without chromium,[116] research interest turned to whether chromium supplementation would benefit people who have type 2 diabetes but are not chromium deficient. Looking at the results from four meta-analyses, one reported a statistically significant decrease in fasting plasma glucose levels (FPG) and a non-significant trend in lower hemoglobin A1C.[122] A second reported the same,[123] a third reported significant decreases for both measures,[124] while a fourth reported no benefit for either.[125] A review published in 2016 listed 53 randomized clinical trials that were included in one or more of six meta-analyses. It concluded that whereas there may be modest decreases in FPG and/or HbA1C that achieve statistical significance in some of these meta-analyses, few of the trials achieved decreases large enough to be expected to be relevant to clinical outcome.[126]

Two systematic reviews looked at chromium supplements as a mean of managing body weight in overweight and obese people. One, limited to chromium picolinate, a popular supplement ingredient, reported a statistically significant −1.1 kg (2.4 lb) weight loss in trials longer than 12 weeks.[127] The other included all chromium compounds and reported a statistically significant −0.50 kg (1.1 lb) weight change.[128] Change in percent body fat did not reach statistical significance. Authors of both reviews considered the clinical relevance of this modest weight loss as uncertain/unreliable.[127][128] The European Food Safety Authority reviewed the literature and concluded that there was insufficient evidence to support a claim.[121]

Chromium is promoted as a sports performance dietary supplement, based on the theory that it potentiates insulin activity, with anticipated results of increased muscle mass, and faster recovery of glycogen storage during post-exercise recovery.[118][129][130] A review of clinical trials reported that chromium supplementation did not improve exercise performance or increase muscle strength.[131] The International Olympic Committee reviewed dietary supplements for high-performance athletes in 2018 and concluded there was no need to increase chromium intake for athletes, nor support for claims of losing body fat.[132]

Fresh-water fish

Chromium is naturally present in the environment in trace amounts, but industrial use in rubber and stainless steel manufacturing, chrome plating, dyes for textiles, tanneries and other uses contaminates aquatic systems. In Bangladesh, rivers in or downstream from industrialized areas exhibit heavy metal contamination. Irrigation water standards for chromium are 0.1 mg/L, but some rivers are more than five times that amount. The standard for fish for human consumption is less than 1 mg/kg, but many tested samples were more than five times that amount.[133] Chromium, especially hexavalent chromium, is highly toxic to fish because it is easily absorbed across the gills, readily enters blood circulation, crosses cell membranes and bioconcentrates up the food chain. In contrast, the toxicity of trivalent chromium is very low, attributed to poor membrane permeability and little biomagnification.[134]

Acute and chronic exposure to chromium(VI) affects fish behavior, physiology, reproduction and survival. Hyperactivity and erratic swimming have been reported in contaminated environments. Egg hatching and fingerling survival are affected. In adult fish there are reports of histopathological damage to liver, kidney, muscle, intestines, and gills. Mechanisms include mutagenic gene damage and disruptions of enzyme functions.[134]

There is evidence that fish may not require chromium, but benefit from a measured amount in diet. In one study, juvenile fish gained weight on a zero chromium diet, but the addition of 500 μg of chromium in the form of chromium chloride or other supplement types, per kilogram of food (dry weight), increased weight gain. At 2,000 μg/kg the weight gain was no better than with the zero chromium diet, and there were increased DNA strand breaks.[135]

Precautions

Main article: Chromium toxicity

Water-insoluble chromium(III) compounds and chromium metal are not considered a health hazard, while the toxicity and carcinogenic properties of chromium(VI) have been known for a long time.[136] Because of the specific transport mechanisms, only limited amounts of chromium(III) enter the cells. Acute oral toxicity ranges between 50 and 150 mg/kg.[137] A 2008 review suggested that moderate uptake of chromium(III) through dietary supplements poses no genetic-toxic risk.[138] In the US, the Occupational Safety and Health Administration (OSHA) has designated an air permissible exposure limit (PEL) in the workplace as a time-weighted average (TWA) of 1 mg/m3. The National Institute for Occupational Safety and Health (NIOSH) has set a recommended exposure limit (REL) of 0.5 mg/m3, time-weighted average. The IDLH (immediately dangerous to life and health) value is 250 mg/m3.[139]

Chromium(VI) toxicity

The acute oral toxicity for chromium(VI) ranges between 1.5 and 3.3 mg/kg.[137] In the body, chromium(VI) is reduced by several mechanisms to chromium(III) already in the blood before it enters the cells. The chromium(III) is excreted from the body, whereas the chromate ion is transferred into the cell by a transport mechanism, by which also sulfate and phosphate ions enter the cell. The acute toxicity of chromium(VI) is due to its strong oxidant properties. After it reaches the blood stream, it damages the kidneys, the liver and blood cells through oxidation reactions. Hemolysis, renal, and liver failure result. Aggressive dialysis can be therapeutic.[140]

The carcinogenity of chromate dust has been known for a long time, and in 1890 the first publication described the elevated cancer risk of workers in a chromate dye company.[141][142] Three mechanisms have been proposed to describe the genotoxicity of chromium(VI). The first mechanism includes highly reactive hydroxyl radicals and other reactive radicals which are by products of the reduction of chromium(VI) to chromium(III). The second process includes the direct binding of chromium(V), produced by reduction in the cell, and chromium(IV) compounds to the DNA. The last mechanism attributed the genotoxicity to the binding to the DNA of the end product of the chromium(III) reduction.[143][144]

Chromium salts (chromates) are also the cause of allergic reactions in some people. Chromates are often used to manufacture, amongst other things, leather products, paints, cement, mortar and anti-corrosives. Contact with products containing chromates can lead to allergic contact dermatitis and irritant dermatitis, resulting in ulceration of the skin, sometimes referred to as "chrome ulcers". This condition is often found in workers that have been exposed to strong chromate solutions in electroplating, tanning and chrome-producing manufacturers.[145][146]

Environmental issues

Because chromium compounds were used in dyes, paints, and leather tanning compounds, these compounds are often found in soil and groundwater at active and abandoned industrial sites, needing environmental cleanup and remediation. Primer paint containing hexavalent chromium is still widely used for aerospace and automobile refinishing applications.[147]

In 2010, the Environmental Working Group studied the drinking water in 35 American cities in the first nationwide study. The study found measurable hexavalent chromium in the tap water of 31 of the cities sampled, with Norman, Oklahoma, at the top of list; 25 cities had levels that exceeded California's proposed limit.[148]

The more toxic hexavalent chromium form can be reduced to the less soluble trivalent oxidation state in soils by organic matter, ferrous iron, sulfides, and other reducing agents, with the rates of such reduction being faster under more acidic conditions than under more alkaline ones. In contrast, trivalent chromium can be oxidized to hexavalent chromium in soils by manganese oxides, such as Mn(III) and Mn(IV) compounds. Since the solubility and toxicity of chromium (VI) are greater that those of chromium (III), the oxidation-reduction conversions between the two oxidation states have implications for movement and bioavailability of chromium in soils, groundwater, and plants.[149]

Notes

  1. ^ The melting/boiling point of transition metals are usually higher compared to the alkali metals, alkaline earth metals, and nonmetals, which is why the range of elements compared to chromium differed between comparisons
  2. ^ Most common oxidation states of chromium are in bold. The right column lists a representative compound for each oxidation state.
  3. ^ Any color of corundum (disregarding red) is known as a sapphire. If the corundum is red, then it is a ruby. Sapphires are not required to be blue corundum crystals, as sapphires can be other colors such as yellow and purple
  4. ^ When Cr3+
     replaces Al3+
     in corundum (aluminium oxide, Al2O3), pink sapphire or ruby is formed, depending on the amount of chromium.

References

  1. ^ "Standard Atomic Weights: Chromium". CIAAW. 1983.
  2. ^ a b Fawcett, Eric (1988). "Spin-density-wave antiferromagnetism in chromium". Reviews of Modern Physics. 60: 209. Bibcode:1988RvMP...60..209F. doi:10.1103/RevModPhys.60.209.
  3. ^ Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.
  4. ^ Brandes, EA; Greenaway, HT; Stone, HEN (1956). "Ductility in Chromium". Nature. 178 (4533): 587. Bibcode:1956Natur.178..587B. doi:10.1038/178587a0. S2CID 4221048.
  5. ^ a b c Coblentz, WW; Stair, R. "Reflecting power of beryllium, chromium, and several other metals" (PDF). National Institute of Standards and Technology. NIST Publications. Retrieved 11 October 2018.
  6. ^ χρῶμα, Henry George Liddell, Robert Scott, A Greek-English Lexicon, on Perseus
  7. ^ a b c d e f "Chromium". Office of Dietary Supplements, US National Institutes of Health. 2016. Retrieved 26 June 2016.
  8. ^ "Scientific Opinion on Dietary Reference Values for chromium". European Food Safety Authority. 18 September 2014. Retrieved 20 March 2018.
  9. ^ "Substance Information - ECHA". echa.europa.eu. Retrieved 17 January 2022.
  10. ^ EPA (August 2000). "Abandoned Mine Site Characterization and Cleanup Handbook" (PDF). United States Environmental Protection Agency. Retrieved 8 September 2019.
  11. ^ "The Nature of X-Ray Photoelectron Spectra". CasaXPS. Casa Software Ltd. 2005. Retrieved 10 March 2019.
  12. ^ Schwarz, W. H. Eugen (April 2010). "The Full Story of the Electron Configurations of the Transition Elements" (PDF). Journal of Chemical Education. 87 (4): 444–8. Bibcode:2010JChEd..87..444S. doi:10.1021/ed8001286. Retrieved 9 November 2018.
  13. ^ Greenwood and Earnshaw, pp. 1004–5
  14. ^ a b Lind, Michael Acton (1972). "The infrared reflectivity of chromium and chromium-aluminium alloys". Iowa State University Digital Repository. Iowa State University. Bibcode:1972PhDT........54L. Retrieved 4 November 2018.
  15. ^ Bos, Laurence William (1969). "Optical properties of chromium-manganese alloys". Iowa State University Digital Repository. Iowa State University. Bibcode:1969PhDT.......118B. Retrieved 4 November 2018.
  16. ^ Wallwork, GR (1976). "The oxidation of alloys". Reports on Progress in Physics. 39 (5): 401–485. Bibcode:1976RPPh...39..401W. doi:10.1088/0034-4885/39/5/001. S2CID 250853920.
  17. ^ a b c d e f g h Holleman, Arnold F; Wiber, Egon; Wiberg, Nils (1985). "Chromium". Lehrbuch der Anorganischen Chemie (in German) (91–100 ed.). Walter de Gruyter. pp. 1081–1095. ISBN 978-3-11-007511-3.
  18. ^ National Research Council (U.S.). Committee on Coatings (1970). High-temperature oxidation-resistant coatings: coatings for protection from oxidation of superalloys, refractory metals, and graphite. National Academy of Sciences. ISBN 978-0-309-01769-5.
  19. ^ a b Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
  20. ^ "Live Chart of Nuclides". International Atomic Energy Agency - Nuclear Data Section. Retrieved 18 October 2018.
  21. ^ Birck, JL; Rotaru, M; Allegre, C (1999). "53Mn-53Cr evolution of the early solar system". Geochimica et Cosmochimica Acta. 63 (23–24): 4111–4117. Bibcode:1999GeCoA..63.4111B. doi:10.1016/S0016-7037(99)00312-9.
  22. ^ Frei, Robert; Gaucher, Claudio; Poulton, Simon W; Canfield, Don E (2009). "Fluctuations in Precambrian atmospheric oxygenation recorded by chromium isotopes". Nature. 461 (7261): 250–253. Bibcode:2009Natur.461..250F. doi:10.1038/nature08266. PMID 19741707. S2CID 4373201.
  23. ^ a b Kotaś, J.; Stasicka, Z. (2000). "Chromium occurrence in the environment and methods of its speciation". Environmental Pollution. 107 (3): 263–283. doi:10.1016/S0269-7491(99)00168-2. PMID 15092973.
  24. ^ Puigdomenech, Ignasi Hydra/Medusa Chemical Equilibrium Database and Plotting Software 5 June 2013 at the Wayback Machine (2004) KTH Royal Institute of Technology
  25. ^ Clark, Jim. "Oxidation states (oxidation numbers)". Chemguide. Retrieved 3 October 2018.
  26. ^ a b Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
  27. ^ Theopold, Klaus H.; Kucharczyk, Robin R. (15 December 2011), "Chromium: Organometallic Chemistry", in Scott, Robert A. (ed.), Encyclopedia of Inorganic and Bioinorganic Chemistry, John Wiley & Sons, Ltd, pp. eibc0042, doi:10.1002/9781119951438.eibc0042, ISBN 978-1-119-95143-8.
  28. ^ Cotton, FA; Walton, RA (1993). Multiple Bonds Between Metal Atoms. Oxford: Oxford University Press. ISBN 978-0-19-855649-7.
  29. ^ "Chromium(III) compounds". National Pollutant Inventory. Commonwealth of Australia. Retrieved 8 November 2018.
  30. ^ Assfalg, M; Banci, L; Bertini, I; Bruschi, M; Michel, C; Giudici-Orticoni, M; Turano, P (31 July 2002). "NMR structural characterization of the reduction of chromium(VI) to chromium(III) by cytochrome c7". Protein Data Bank (1LM2). doi:10.2210/pdb1LM2/pdb. Retrieved 8 November 2018.
  31. ^ Luther, George W. (2016). "Introduction to Transition Metals". Inorganic Chemistry for Geochemistry & Environmental Sciences: Fundamentals & Applications. Hydrate (Solvate) Isomers. John Wiley & Sons. p. 244. ISBN 978-1118851371. Retrieved 7 August 2019.
  32. ^ Gumerova, Nadiia I.; Roller, Alexander; Giester, Gerald; Krzystek, J.; Cano, Joan; Rompel, Annette (19 February 2020). "Incorporation of CrIII into a Keggin Polyoxometalate as a Chemical Strategy to Stabilize a Labile {CrIIIO4} Tetrahedral Conformation and Promote Unattended Single-Ion Magnet Properties". Journal of the American Chemical Society. 142 (7): 3336–3339. doi:10.1021/jacs.9b12797. ISSN 0002-7863. PMC 7052816. PMID 31967803.
  33. ^ Seppelt, Konrad (28 January 2015). "Molecular Hexafluorides". Chemical Reviews. 115 (2): 1296–1306. doi:10.1021/cr5001783. ISSN 0009-2665. PMID 25418862.
  34. ^ Haxhillazi, Gentiana (2003). Preparation, Structure and Vibrational Spectroscopy of Tetraperoxo Complexes of CrV+, VV+, NbV+ and TaV+ (PhD thesis). University of Siegen.
  35. ^ Thaler, Eric G.; Rypdal, Kristin; Haaland, Arne; Caulton, Kenneth G. (1 June 1989). "Structure and reactivity of chromium(4+) tert-butoxide". Inorganic Chemistry. 28 (12): 2431–2434. doi:10.1021/ic00311a035. ISSN 0020-1669.
  36. ^ Nguyen, T; Sutton, AD; Brynda, M; Fettinger, JC; Long, GJ; Power, PP (2005). "Synthesis of a stable compound with fivefold bonding between two chromium(I) centers". Science. 310 (5749): 844–847. Bibcode:2005Sci...310..844N. doi:10.1126/science.1116789. PMID 16179432. S2CID 42853922.
  37. ^ Emsley, John (2001). "Chromium". Nature's Building Blocks: An A–Z Guide to the Elements. Oxford, England, UK: Oxford University Press. pp. 495–498. ISBN 978-0-19-850340-8.
  38. ^ John Rieuwerts (14 July 2017). The Elements of Environmental Pollution. Taylor & Francis. ISBN 978-1-135-12679-7.
  39. ^ a b c National Research Council (U.S.). Committee on Biologic Effects of Atmospheric Pollutants (1974). Chromium. National Academy of Sciences. ISBN 978-0-309-02217-0.
  40. ^ Champion, Marc (11 January 2018). "How a Trump SoHo Partner Ended Up With Toxic Mining Riches From Kazakhstan". Bloomberg.com. Bloomberg L.P. Retrieved 21 January 2018.
  41. ^ a b c d Papp, John F. "Mineral Yearbook 2015: Chromium" (PDF). United States Geological Survey. Retrieved 3 June 2015.
  42. ^ Fleischer, Michael (1982). "New Mineral Names" (PDF). American Mineralogist. 67: 854–860.
  43. ^ Chromium (with location data), Mindat.
  44. ^ Chromium from Udachnaya-Vostochnaya pipe, Daldyn, Daldyn-Alakit kimberlite field, Saha Republic (Sakha Republic; Yakutia), Eastern-Siberian Region, Russia, Mindat.
  45. ^ Gonzalez, A. R.; Ndung'u, K.; Flegal, A. R. (2005). "Natural Occurrence of Hexavalent Chromium in the Aromas Red Sands Aquifer, California". Environmental Science and Technology. 39 (15): 5505–5511. Bibcode:2005EnST...39.5505G. doi:10.1021/es048835n. PMID 16124280.
  46. ^ Meyer, RJ (1962). Chrom : Teil A - Lieferung 1. Geschichtliches · Vorkommen · Technologie · Element bis Physikalische Eigenschaften (in German). Berlin, Heidelberg: Springer Berlin Heidelberg Imprint Springer. ISBN 978-3-662-11865-8. OCLC 913810356.
  47. ^ Lehmanni, Iohannis Gottlob (1766). De Nova Minerae Plumbi Specie Crystallina Rubra, Epistola.
  48. ^ a b c Guertin, Jacques; Jacobs, James Alan & Avakian, Cynthia P. (2005). Chromium (VI) Handbook. CRC Press. pp. 7–11. ISBN 978-1-56670-608-7.
  49. ^ Weeks, Mary Elvira (1932). "The discovery of the elements. V. Chromium, molybdenum, tungsten and uranium". Journal of Chemical Education. 9 (3): 459–73. Bibcode:1932JChEd...9..459W. doi:10.1021/ed009p459. ISSN 0021-9584.
  50. ^ Casteran, Rene. "Chromite mining". Oregon Encyclopedia. Portland State University and the Oregon Historical Society. Retrieved 1 October 2018.
  51. ^ Vauquelin, Louis Nicolas (1798). "Memoir on a New Metallic Acid which exists in the Red Lead of Siberia". Journal of Natural Philosophy, Chemistry, and the Arts. 3: 145–146.
  52. ^ Glenn, William (1895). "Chrome in the Southern Appalachian Region". Transactions of the American Institute of Mining, Metallurgical and Petroleum Engineers. 25: 482.
  53. ^ van der Krogt, Peter. "Chromium". Retrieved 24 August 2008.
  54. ^ Ortt, Richard A Jr. "Soldier's Delight, Baltimore Country". Maryland Department of Natural Resources. Maryland Geological Survey. Retrieved 13 May 2019.
  55. ^ Bilgin, Arif; Çağlar, Burhan (eds.). Klasikten Moderne Osmanlı Ekonomisi. Turkey: Kronik Kitap. p. 240.
  56. ^ a b c Dennis, JK; Such, TE (1993). "History of Chromium Plating". Nickel and Chromium Plating. Woodhead Publishing. pp. 9–12. ISBN 978-1-85573-081-6.
  57. ^ a b c d Papp, John F. & Lipin, Bruce R. (2006). "Chromite". Industrial Minerals & Rocks: Commodities, Markets, and Uses (7th ed.). SME. ISBN 978-0-87335-233-8.
  58. ^ Papp, John F. "Mineral Yearbook 2002: Chromium" (PDF). United States Geological Survey. Retrieved 16 February 2009.
  59. ^ Morrison, RD; Murphy, BL (4 August 2010). Environmental Forensics: Contaminant Specific Guide. Academic Press. ISBN 9780080494784.
  60. ^ Davis, JR (2000). Alloy digest sourcebook : stainless steels (in Afrikaans). Materials Park, OH: ASM International. pp. 1–5. ISBN 978-0-87170-649-2. OCLC 43083287.
  61. ^ Bhadeshia, HK. . University of Cambridge. Archived from the original on 25 August 2006. Retrieved 17 February 2009.
  62. ^ "Chromium, Nickel and Welding". IARC Monographs. International Agency for Research on Cancer. 49: 49–50. 1990.
  63. ^ "Stainless Steel Grade 332 (UNS S33200)". AZoNetwork. 5 March 2013.
  64. ^ "Super Alloy INCOLOY Alloy 800 (UNS N08800)". AZoNetwork. 3 July 2013.
  65. ^ "Manual On Uniform Traffic Control Devices (War Emergency Edition)" (PDF). Washington, DC: American Associan of State Highway Officials. November 1942. p. 52. Retrieved 8 July 2021.
  66. ^ State Department, United States. "Allied Relations and Negotiations with Turkey" (PDF). (PDF) from the original on 9 November 2020.
  67. ^ Breitsameter, M (15 August 2002). "Thermal Spraying versus Hard Chrome Plating". Azo Materials. AZoNetwork. Retrieved 1 October 2018.
  68. ^ Edwards, J (1997). Coating and Surface Treatment Systems for Metals. Finishing Publications Ltd. and ASMy International. pp. 66–71. ISBN 978-0-904477-16-0.
  69. ^ Zhao J, Xia L, Sehgal A, Lu D, McCreery RL, Frankel GS (2001). "Effects of chromate and chromate conversion coatings on corrosion of aluminum alloy 2024-T3". Surface and Coatings Technology. 140 (1): 51–57. doi:10.1016/S0257-8972(01)01003-9. hdl:1811/36519.
  70. ^ Cotell, CM; Sprague, JA; Smidt, FA (1994). ASM Handbook: Surface Engineering. ASM International. ISBN 978-0-87170-384-2. Retrieved 17 February 2009.
  71. ^ Gettens, Rutherford John (1966). "Chrome yellow". Painting Materials: A Short Encyclopaedia. Courier Dover Publications. pp. 105–106. ISBN 978-0-486-21597-6.
  72. ^ Gerd Anger et al. "Chromium Compounds" Ullmann's Encyclopedia of Industrial Chemistry 2005, Wiley-VCH, Weinheim. doi:10.1002/14356007.a07_067
  73. ^ Marrion, Alastair (2004). The chemistry and physics of coatings. Royal Society of Chemistry. pp. 287–. ISBN 978-0-85404-604-1.
  74. ^ Moss, SC; Newnham, RE (1964). "The chromium position in ruby" (PDF). Zeitschrift für Kristallographie. 120 (4–5): 359–363. Bibcode:1964ZK....120..359M. doi:10.1524/zkri.1964.120.4-5.359.
  75. ^ Webb, Colin E; Jones, Julian DC (2004). Handbook of Laser Technology and Applications: Laser design and laser systems. CRC Press. pp. 323–. ISBN 978-0-7503-0963-9.
  76. ^ a b Hingston, J; Collins, CD; Murphy, RJ; Lester, JN (2001). "Leaching of chromated copper arsenate wood preservatives: a review". Environmental Pollution. 111 (1): 53–66. doi:10.1016/S0269-7491(00)00030-0. PMID 11202715.
  77. ^ Brown, EM (1997). "A Conformational Study of Collagen as Affected by Tanning Procedures". Journal of the American Leather Chemists Association. 92: 225–233.
  78. ^ Sreeram, K.; Ramasami, T. (2003). "Sustaining tanning process through conservation, recovery and better utilization of chromium". Resources, Conservation and Recycling. 38 (3): 185–212. doi:10.1016/S0921-3449(02)00151-9.
  79. ^ Qiang, Taotao; Gao, Xin; Ren, Jing; Chen, Xiaoke; Wang, Xuechuan (9 December 2015). "A Chrome-Free and Chrome-Less Tanning System Based on the Hyperbranched Polymer". ACS Sustainable Chemistry & Engineering. 4 (3): 701–707. doi:10.1021/acssuschemeng.5b00917.
  80. ^ Barnhart, Joel (1997). "Occurrences, Uses, and Properties of Chromium". Regulatory Toxicology and Pharmacology. 26 (1): S3–S7. doi:10.1006/rtph.1997.1132. ISSN 0273-2300. PMID 9380835.
  81. ^ Weckhuysen, Bert M; Schoonheydt, Robert A (1999). "Olefin polymerization over supported chromium oxide catalysts" (PDF). Catalysis Today. 51 (2): 215–221. doi:10.1016/S0920-5861(99)00046-2. hdl:1874/21357. S2CID 98324455.
  82. ^ Twigg, MVE (1989). "The Water-Gas Shift Reaction". Catalyst Handbook. ISBN 978-0-7234-0857-4.
  83. ^ Rhodes, C; Hutchings, GJ; Ward, AM (1995). "Water-gas shift reaction: Finding the mechanistic boundary". Catalysis Today. 23: 43–58. doi:10.1016/0920-5861(94)00135-O.
  84. ^ Lazier, WA & Arnold, HR (1939). "Copper Chromite Catalyst". Organic Syntheses. 19: 31.; Collective Volume, vol. 2, p. 142
  85. ^ Kitagawa, Hiraku (April 1989). "LiTe and CaTe thin-film junctions as humidity sensors". Sensors and Actuators. 16 (4): 369–378. doi:10.1016/0250-6874(89)85007-3.
  86. ^ Mallinson, John C. (1993). "Chromium Dioxide". The foundations of magnetic recording. Academic Press. p. 32. ISBN 978-0-12-466626-9.
  87. ^ Toshiro Doi; Ioan D. Marinescu; Syuhei Kurokawa (30 November 2011). Advances in CMP Polishing Technologies. William Andrew. pp. 60–. ISBN 978-1-4377-7860-1.
  88. ^ Baral, Anil; Engelken, Robert D. (2002). "Chromium-based regulations and greening in metal finishing industries in the USA". Environmental Science & Policy. 5 (2): 121–133. doi:10.1016/S1462-9011(02)00028-X.
  89. ^ Soderberg, Tim (3 June 2019). "Oxidizing Agents". LibreTexts. MindTouch. Retrieved 8 September 2019.
  90. ^ Roth, Alexander (1994). Vacuum Sealing Techniques. Springer Science & Business Media. pp. 118–. ISBN 978-1-56396-259-2.
  91. ^ Lancashire, Robert J (27 October 2008). "Determination of iron using potassium dichromate: Redox indicators". The Department of Chemistry UWI, Jamaica. Retrieved 8 September 2019.
  92. ^ Garverick, Linda (1994). Corrosion in the Petrochemical Industry. ASM International. ISBN 978-0-87170-505-1.
  93. ^ Shahid Ul-Islam (18 July 2017). Plant-Based Natural Products: Derivatives and Applications. Wiley. pp. 74–. ISBN 978-1-119-42388-1.
  94. ^ Vincent, JB (2013). "Chapter 6. Chromium: Is It Essential, Pharmacologically Relevant, or Toxic?". In Astrid Sigel; Helmut Sigel; Roland KO Sigel (eds.). Interrelations between Essential Metal Ions and Human Diseases. Metal Ions in Life Sciences. Vol. 13. Springer. pp. 171–198. doi:10.1007/978-94-007-7500-8_6. ISBN 978-94-007-7499-5. PMID 24470092.
  95. ^ Maret, Wolfgang (2019). "Chapter 9. Chromium Supplementation in Human Health, Metabolic Syndrome, and Diabetes". In Sigel, Astrid; Freisinger, Eva; Sigel, Roland K. O.; Carver, Peggy L. (eds.). Essential Metals in Medicine:Therapeutic Use and Toxicity of Metal Ions in the Clinic. Metal Ions in Life Sciences. Vol. 19. Berlin: de Gruyter GmbH. pp. 231–251. doi:10.1515/9783110527872-015. ISBN 978-3-11-052691-2. PMID 30855110.
  96. ^ European Food Safety Authority (2014). "Scientific Opinion on Dietary Reference Values for chromium". EFSA Journal. 12 (10): 3845. doi:10.2903/j.efsa.2014.3845.
  97. ^ Di Bona KR, Love S, Rhodes NR, McAdory D, Sinha SH, Kern N, Kent J, Strickland J, Wilson A, Beaird J, Ramage J, Rasco JF, Vincent JB (2011). "Chromium is not an essential trace element for mammals: effects of a "low-chromium" diet". J Biol Inorg Chem. 16 (3): 381–390. doi:10.1007/s00775-010-0734-y. PMID 21086001. S2CID 22376660.
  98. ^ Wise, SS; Wise, JP, Sr (2012). "Chromium and genomic stability". Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis. 733 (1–2): 78–82. doi:10.1016/j.mrfmmm.2011.12.002. PMC 4138963. PMID 22192535.
  99. ^ . Agency for Toxic Substances & Disease Registry, Centers for Disease Control and Prevention. February 2001. Archived from the original on 8 July 2014. Retrieved 2 October 2007.
  100. ^ Vincent, JB (2015). "Is the Pharmacological Mode of Action of Chromium(III) as a Second Messenger?". Biological Trace Element Research. 166 (1): 7–12. doi:10.1007/s12011-015-0231-9. PMID 25595680. S2CID 16895342.
  101. ^ a b Thor, MY; Harnack, L; King, D; Jasthi, B; Pettit, J (2011). "Evaluation of the comprehensiveness and reliability of the chromium composition of foods in the literature". Journal of Food Composition and Analysis. 24 (8): 1147–1152. doi:10.1016/j.jfca.2011.04.006. PMC 3467697. PMID 23066174.
  102. ^ Kamerud KL; Hobbie KA; Anderson KA (2013). "Stainless steel leaches nickel and chromium into foods during cooking". Journal of Agricultural and Food Chemistry. 61 (39): 9495–9501. doi:10.1021/jf402400v. PMC 4284091. PMID 23984718.
  103. ^ Flint GN; Packirisamy S (1997). "Purity of food cooked in stainless steel utensils". Food Additives and Contaminants. 14 (2): 115–126. doi:10.1080/02652039709374506. PMID 9102344.
  104. ^ a b "Chromium". Nutrient Reference Values for Australia and New Zealand. 2014. Retrieved 4 October 2018.
  105. ^ a b (PDF). Archived from the original (PDF) on 15 June 2016. Retrieved 3 October 2018.
  106. ^ a b "DRIs for Chromium (μg/day)" (PDF). Overview of Dietary Reference Intakes for Japanese. 2015. p. 41. Retrieved 4 October 2018.
  107. ^ a b c "Chromium. IN: Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Chromium, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Chromium". Institute of Medicine (U.S.) Panel on Micronutrients, National Academy Press. 2001. pp. 197–223. Retrieved 3 October 2018.
  108. ^ a b "Overview on Dietary Reference Values for the EU population as derived by the EFSA Panel on Dietetic Products, Nutrition and Allergies" (PDF). 2017.
  109. ^ Tolerable Upper Intake Levels For Vitamins And Minerals (PDF), European Food Safety Authority, 2006
  110. ^ "Federal Register May 27, 2016 Food Labeling: Revision of the Nutrition and Supplement Facts Labels. FR page 33982" (PDF).
  111. ^ . Dietary Supplement Label Database (DSLD). Archived from the original on 7 April 2020. Retrieved 16 May 2020.
  112. ^ "USDA Food Composition Databases". United States Department of Agriculture Agricultural Research Service. April 2018. Retrieved 4 October 2018.
  113. ^ Kumpulainen, JT (1992). "Chromium content of foods and diets". Biological Trace Element Research. 32 (1–3): 9–18. doi:10.1007/BF02784582. PMID 1375091. S2CID 10189109.
  114. ^ Grijalva Haro, MI; Ballesteros Vázquez, MN; Cabrera Pacheco, RM (2001). "Chromium content in foods and dietary intake estimation in the Northwest of Mexico". Arch Latinoam Nutr (in Spanish). 51 (1): 105–110. PMID 11515227.
  115. ^ a b Kantor, Elizabeth D; Rehm, Colin D; Du, Mengmeng; White, Emily; Giovannucci, Edward L (11 October 2017). "Trends in Dietary Supplement Use Among US Adults From 1999-2012". JAMA. 316 (14): 1464–1474. doi:10.1001/jama.2016.14403. PMC 5540241. PMID 27727382.
  116. ^ a b Stehle, P; Stoffel-Wagner, B; Kuh, KS (6 April 2014). "Parenteral trace element provision: recent clinical research and practical conclusions". European Journal of Clinical Nutrition. 70 (8): 886–893. doi:10.1038/ejcn.2016.53. PMC 5399133. PMID 27049031.
  117. ^ Finch, Carolyn Weiglein (February 2015). "Review of trace mineral requirements for preterm infants: What are the current recommendations for clinical practice?". Nutrition in Clinical Practice. 30 (1): 44–58. doi:10.1177/0884533614563353. PMID 25527182.
  118. ^ a b Vincent, John B (2010). "Chromium: Celebrating 50 years as an essential element?". Dalton Transactions. 39 (16): 3787–3794. doi:10.1039/B920480F. PMID 20372701.
  119. ^ FDA Qualified Health Claims: Letters of Enforcement Discretion, Letters of Denial U.S. Food and Drug Administration, Docket #2004Q-0144 (August 2005).
  120. ^ "Monograph: Chromium (from Chromium picolinate)". Health Canada. 9 December 2009. Retrieved 18 October 2018.
  121. ^ a b Scientific Opinion on the substantiation of health claims related to chromium and contribution to normal macronutrient metabolism (ID 260, 401, 4665, 4666, 4667), maintenance of normal blood glucose concentrations (ID 262, 4667), contribution to the maintenance or achievement of a normal body weight (ID 339, 4665, 4666), and reduction of tiredness and fatigue (ID 261) pursuant to Article 13(1) of Regulation (EC) No 1924/2006 21 April 2020 at the Wayback Machine European Food Safety Authority EFSA J 2010;8(10)1732.
  122. ^ San Mauro-Martin I, Ruiz-León AM, Camina-Martín MA, Garicano-Vilar E, Collado-Yurrita L, Mateo-Silleras B, Redondo P (2016). "[Chromium supplementation in patients with type 2 diabetes and high risk of type 2 diabetes: a meta-analysis of randomized controlled trials]". Nutr Hosp (in Spanish). 33 (1): 27. doi:10.20960/nh.27. PMID 27019254.
  123. ^ Abdollahi, M; Farshchi, A; Nikfar, S; Seyedifar, M (2013). "Effect of chromium on glucose and lipid profiles in patients with type 2 diabetes; a meta-analysis review of randomized trials". J Pharm Pharm Sci. 16 (1): 99–114. doi:10.18433/J3G022. PMID 23683609.
  124. ^ Suksomboon, N; Poolsup, N; Yuwanakorn, A (17 March 2013). "Systematic review and meta-analysis of the efficacy and safety of chromium supplementation in diabetes". J Clin Pharm Ther. 39 (3): 292–306. doi:10.1111/jcpt.12147. PMID 24635480. S2CID 22326435.
  125. ^ Bailey, Christopher H (January 2014). "Improved meta-analytic methods show no effect of chromium supplements on fasting glucose". Biol Trace Elem Res. 157 (1): 1–8. doi:10.1007/s12011-013-9863-9. PMID 24293356. S2CID 2441511.
  126. ^ Costello, Rebecca B; Dwyer, Johanna T; Bailey, Regan L (30 May 2016). "Chromium supplements for glycemic control in type 2 diabetes: limited evidence of effectiveness". Nutrition Reviews. 74 (7): 455–468. doi:10.1093/nutrit/nuw011. PMC 5009459. PMID 27261273.
  127. ^ a b Tian, Honglian; Guo, Xiaohu; Wang, Xiyu; He, Zhiyun; Sun, Rao; Ge, Sai; Zhang, Zongjiu (2013). "Chromium picolinate supplementation for overweight or obese adults". Cochrane Database Syst Rev. 2013 (11): CD010063. doi:10.1002/14651858.CD010063.pub2. PMC 7433292. PMID 24293292.
  128. ^ a b Onakpoya, I; Posadzki, P; Ernst, E (2013). "Chromium supplementation in overweight and obesity: a systematic review and meta-analysis of randomized clinical trials". Obes Rev. 14 (6): 496–507. doi:10.1111/obr.12026. PMID 23495911. S2CID 21832321.
  129. ^ Lefavi RG, Anderson RA, Keith RE, Wilson GD, McMillan JL, Stone MH (1992). "Efficacy of chromium supplementation in athletes: emphasis on anabolism". International Journal of Sport Nutrition. 2 (2): 111–122. doi:10.1123/ijsn.2.2.111. PMID 1299487.
  130. ^ Vincent JB (2003). "The potential value and toxicity of chromium picolinate as a nutritional supplement, weight loss agent and muscle development agent". Sports Med. 33 (3): 213–230. doi:10.2165/00007256-200333030-00004. PMID 12656641. S2CID 9981172.
  131. ^ Jenkinson DM, Harbert AJ (2008). "Supplements and sports". Am Fam Physician. 78 (9): 1039–1046. PMID 19007050.
  132. ^ Maughan RJ, Burke LM, et al. (2018). "IOC Consensus Statement: Dietary Supplements and the High-Performance Athlete". International Journal of Sport Nutrition and Exercise Metabolism. 28 (2): 104–125. doi:10.1123/ijsnem.2018-0020. PMC 5867441. PMID 29589768.
  133. ^ Islam MM, Karim MR, Zheng X, Li X (2018). "Heavy Metal and Metalloid Pollution of Soil, Water and Foods in Bangladesh: A Critical Review". International Journal of Environmental Research and Public Health. 15 (12): 2825. doi:10.3390/ijerph15122825. PMC 6313774. PMID 30544988.
  134. ^ a b Bakshi A, Panigrahi AK (2018). "A comprehensive review on chromium induced alterations in fresh water fishes". Toxicol Rep. 5: 440–447. doi:10.1016/j.toxrep.2018.03.007. PMC 5977408. PMID 29854615.
  135. ^ Ahmed AR, Jha AN, Davies SJ (2012). "The efficacy of chromium as a growth enhancer for mirror carp (Cyprinus carpio L): an integrated study using biochemical, genetic, and histological responses". Biol Trace Elem Res. 148 (2): 187–197. doi:10.1007/s12011-012-9354-4. PMID 22351105. S2CID 16154712.
  136. ^ Barceloux, Donald G; Barceloux, Donald (1999). "Chromium". Clinical Toxicology. 37 (2): 173–194. doi:10.1081/CLT-100102418. PMID 10382554.
  137. ^ a b Katz, SA; Salem, H (1992). "The toxicology of chromium with respect to its chemical speciation: A review". Journal of Applied Toxicology. 13 (3): 217–224. doi:10.1002/jat.2550130314. PMID 8326093. S2CID 31117557.
  138. ^ Eastmond, DA; MacGregor, JT; Slesinski, RS (2008). "Trivalent Chromium: Assessing the Genotoxic Risk of an Essential Trace Element and Widely Used Human and Animal Nutritional Supplement". Critical Reviews in Toxicology. 38 (3): 173–190. doi:10.1080/10408440701845401. PMID 18324515. S2CID 21033504.
  139. ^ NIOSH Pocket Guide to Chemical Hazards. "#0141". National Institute for Occupational Safety and Health (NIOSH).
  140. ^ Dayan, AD; Paine, AJ (2001). "Mechanisms of chromium toxicity, carcinogenicity and allergenicity: Review of the literature from 1985 to 2000". Human & Experimental Toxicology. 20 (9): 439–451. doi:10.1191/096032701682693062. PMID 11776406. S2CID 31351037.
  141. ^ Newman, D. (1890). "A case of adeno-carcinoma of the left inferior turbinated body, and perforation of the nasal septum, in the person of a worker in chrome pigments". Glasgow Medical Journal. 33: 469–470.
  142. ^ Langard, S (1990). "One Hundred Years of Chromium and Cancer: A Review of Epidemiological Evidence and Selected Case Reports". American Journal of Industrial Medicine. 17 (2): 189–214. doi:10.1002/ajim.4700170205. PMID 2405656.
  143. ^ Cohen, MD; Kargacin, B; Klein, CB; Costa, M (1993). "Mechanisms of chromium carcinogenicity and toxicity". Critical Reviews in Toxicology. 23 (3): 255–281. doi:10.3109/10408449309105012. PMID 8260068.
  144. ^ Methods to Develop Inhalation Cancer Risk Estimates for Chromium and Nickel Compounds. Research Triangle Park, NC: U.S. Environmental Protection Agency, Office of Air Quality Planning and Standards, Health and Environmental Impacts Division. 2011. Retrieved 19 March 2015.
  145. ^ Ngan, V (2002). "Chrome Allergy". DermNet NZ.
  146. ^ Basketter, David; Horev, L; Slodovnik, D; Merimes, S; Trattner, A; Ingber, A (2000). "Investigation of the threshold for allergic reactivity to chromium". Contact Dermatitis. 44 (2): 70–74. doi:10.1034/j.1600-0536.2001.440202.x. PMID 11205406. S2CID 45426346.
  147. ^ Baselt, Randall C (2008). Disposition of Toxic Drugs and Chemicals in Man (8th ed.). Foster City: Biomedical Publications. pp. 305–307. ISBN 978-0-9626523-7-0.
  148. ^ . Yahoo News. 19 December 2010. Archived from the original on 23 December 2010. Retrieved 19 December 2010.
  149. ^ James, Bruce (1996). "The challenge of remediating chromium-contaminated soil". Environmental Science and Technology. 30 (6): 248A–251A. doi:10.1021/es962269h. PMID 21648723.

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February 08, 2023
chromium, this, article, about, chemical, element, other, uses, disambiguation, chemical, element, with, symbol, atomic, number, first, element, group, steely, grey, lustrous, hard, brittle, transition, metal, 24crappearancesilvery, metallicstandard, atomic, w. This article is about the chemical element For other uses see Chromium disambiguation Chromium is a chemical element with the symbol Cr and atomic number 24 It is the first element in group 6 It is a steely grey lustrous hard and brittle transition metal 4 Chromium 24CrChromiumAppearancesilvery metallicStandard atomic weight Ar Cr 51 9961 0 000651 996 0 001 abridged 1 Chromium in the periodic tableHydrogen HeliumLithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine NeonSodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine ArgonPotassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine KryptonRubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine XenonCaesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury element Thallium Lead Bismuth Polonium Astatine RadonFrancium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson Cr Movanadium chromium manganeseAtomic number Z 24Groupgroup 6Periodperiod 4Block d blockElectron configuration Ar 3d5 4s1Electrons per shell2 8 13 1Physical propertiesPhase at STPsolidMelting point2180 K 1907 C 3465 F Boiling point2944 K 2671 C 4840 F Density near r t 7 15 g cm3when liquid at m p 6 3 g cm3Heat of fusion21 0 kJ molHeat of vaporization347 kJ molMolar heat capacity23 35 J mol K Vapor pressureP Pa 1 10 100 1 k 10 k 100 kat T K 1656 1807 1991 2223 2530 2942Atomic propertiesOxidation states 4 2 1 0 1 2 3 4 5 6 depending on the oxidation state an acidic basic or amphoteric oxide ElectronegativityPauling scale 1 66Ionization energies1st 652 9 kJ mol2nd 1590 6 kJ mol3rd 2987 kJ mol more Atomic radiusempirical 128 pmCovalent radius139 5 pmSpectral lines of chromiumOther propertiesNatural occurrenceprimordialCrystal structure body centered cubic bcc Speed of sound thin rod5940 m s at 20 C Thermal expansion4 9 µm m K at 25 C Thermal conductivity93 9 W m K Electrical resistivity125 nW m at 20 C Magnetic orderingantiferromagnetic rather SDW 2 Molar magnetic susceptibility 280 0 10 6 cm3 mol 273 K 3 Young s modulus279 GPaShear modulus115 GPaBulk modulus160 GPaPoisson ratio0 21Mohs hardness8 5Vickers hardness1060 MPaBrinell hardness687 6500 MPaCAS Number7440 47 3HistoryDiscovery and first isolationLouis Nicolas Vauquelin 1794 1797 Main isotopes of chromiumveIso tope Decayabun dance half life t1 2 mode pro duct50Cr 4 345 stable51Cr syn 27 7025 d e 51Vg 52Cr 83 789 stable53Cr 9 501 stable54Cr 2 365 stable Category Chromiumviewtalkedit referencesChromium metal is valued for its high corrosion resistance and hardness A major development in steel production was the discovery that steel could be made highly resistant to corrosion and discoloration by adding metallic chromium to form stainless steel Stainless steel and chrome plating electroplating with chromium together comprise 85 of the commercial use Chromium is also greatly valued as a metal that is able to be highly polished while resisting tarnishing Polished chromium reflects almost 70 of the visible spectrum and almost 90 of infrared light 5 The name of the element is derived from the Greek word xrῶma chrōma meaning color 6 because many chromium compounds are intensely colored Industrial production of chromium proceeds from chromite ore mostly FeCr2O4 to produce ferrochromium an iron chromium alloy by means of aluminothermic or silicothermic reactions Ferrochromium is then used to produce alloys such as stainless steel Pure chromium metal is produced by a different process roasting and leaching of chromite to separate it from iron followed by reduction with carbon and then aluminium In the United States trivalent chromium Cr III ion is considered an essential nutrient in humans for insulin sugar and lipid metabolism 7 However in 2014 the European Food Safety Authority acting for the European Union concluded that there was insufficient evidence for chromium to be recognized as essential 8 While chromium metal and Cr III ions are considered non toxic hexavalent chromium Cr VI is toxic and carcinogenic According to the European Chemicals Agency ECHA chromium trioxide that is used in industrial electroplating processes is a substance of very high concern SVHC 9 Abandoned chromium production sites often require environmental cleanup 10 Contents 1 Physical properties 1 1 Atomic 1 2 Bulk 1 2 1 Passivation 1 3 Isotopes 2 Chemistry and compounds 2 1 Common oxidation states 2 1 1 Chromium 0 2 1 2 Chromium II 2 1 3 Chromium III 2 1 4 Chromium VI 2 2 Other oxidation states 3 Occurrence 4 History 4 1 Early applications 5 Production 6 Applications 6 1 Metallurgy 6 2 Pigment 6 3 Other uses 6 4 Uses of compounds 7 Biological role 7 1 Dietary recommendations 7 1 1 Labeling 7 2 Food sources 7 3 Supplementation 7 3 1 Approved and disapproved health claims 7 4 Fresh water fish 8 Precautions 8 1 Chromium VI toxicity 8 2 Environmental issues 9 Notes 10 References 11 General bibliography 12 External linksPhysical properties EditAtomic Edit Chromium is the fourth transition metal found on the periodic table and has an electron configuration of Ar 3d5 4s1 It is also the first element in the periodic table whose ground state electron configuration violates the Aufbau principle This occurs again later in the periodic table with other elements and their electron configurations such as copper niobium and molybdenum 11 This occurs because electrons in the same orbital repel each other due to their like charges In the previous elements the energetic cost of promoting an electron to the next higher energy level is too great to compensate for that released by lessening inter electronic repulsion However in the 3d transition metals the energy gap between the 3d and the next higher 4s subshell is very small and because the 3d subshell is more compact than the 4s subshell inter electron repulsion is smaller between 4s electrons than between 3d electrons This lowers the energetic cost of promotion and increases the energy released by it so that the promotion becomes energetically feasible and one or even two electrons are always promoted to the 4s subshell Similar promotions happen for every transition metal atom but one palladium 12 Chromium is the first element in the 3d series where the 3d electrons start to sink into the nucleus they thus contribute less to metallic bonding and hence the melting and boiling points and the enthalpy of atomisation of chromium are lower than those of the preceding element vanadium Chromium VI is a strong oxidising agent in contrast to the molybdenum VI and tungsten VI oxides 13 Bulk Edit Sample of pure chromium metal Chromium is extremely hard and is the third hardest element behind carbon diamond and boron Its Mohs hardness is 8 5 which means that it can scratch samples of quartz and topaz but can be scratched by corundum Chromium is highly resistant to tarnishing which makes it useful as a metal that preserves its outermost layer from corroding unlike other metals such as copper magnesium and aluminium Chromium has a melting point of 1907 C 3465 F which is relatively low compared to the majority of transition metals However it still has the second highest melting point out of all the Period 4 elements being topped by vanadium by 3 C 5 F at 1910 C 3470 F The boiling point of 2671 C 4840 F however is comparatively lower having the fourth lowest boiling point out of the Period 4 transition metals alone behind copper manganese and zinc note 1 The electrical resistivity of chromium at 20 C is 125 nanoohm meters Chromium has a high specular reflection in comparison to other transition metals In infrared at 425 mm chromium has a maximum reflectance of about 72 reducing to a minimum of 62 at 750 mm before rising again to 90 at 4000 mm 5 When chromium is used in stainless steel alloys and polished the specular reflection decreases with the inclusion of additional metals yet is still high in comparison with other alloys Between 40 and 60 of the visible spectrum is reflected from polished stainless steel 5 The explanation on why chromium displays such a high turnout of reflected photon waves in general especially the 90 in infrared can be attributed to chromium s magnetic properties 14 Chromium has unique magnetic properties chromium is the only elemental solid that shows antiferromagnetic ordering at room temperature and below Above 38 C its magnetic ordering becomes paramagnetic 2 The antiferromagnetic properties which cause the chromium atoms to temporarily ionize and bond with themselves are present because the body centric cubic s magnetic properties are disproportionate to the lattice periodicity This is due to the magnetic moments at the cube s corners and the unequal but antiparallel cube centers 14 From here the frequency dependent relative permittivity of chromium deriving from Maxwell s equations and chromium s antiferromagnetism leaves chromium with a high infrared and visible light reflectance 15 Passivation Edit Chromium metal left standing in air is passivated it forms a thin protective surface layer of oxide This layer has a spinel structure a few atomic layers thick it is very dense and inhibits the diffusion of oxygen into the underlying metal In contrast iron forms a more porous oxide through which oxygen can migrate causing continued rusting 16 Passivation can be enhanced by short contact with oxidizing acids like nitric acid Passivated chromium is stable against acids Passivation can be removed with a strong reducing agent that destroys the protective oxide layer on the metal Chromium metal treated in this way readily dissolves in weak acids 17 Chromium unlike iron and nickel does not suffer from hydrogen embrittlement However it does suffer from nitrogen embrittlement reacting with nitrogen from air and forming brittle nitrides at the high temperatures necessary to work the metal parts 18 Isotopes Edit Main article Isotopes of chromium Naturally occurring chromium is composed of four stable isotopes 50Cr 52Cr 53Cr and 54Cr with 52Cr being the most abundant 83 789 natural abundance 50Cr is observationally stable as it is theoretically capable of decaying to 50Ti via double electron capture with a half life of no less than 1 3 1018 years Twenty five radioisotopes have been characterized ranging from 42Cr to 70Cr the most stable radioisotope is 51Cr with a half life of 27 7 days All of the remaining radioactive isotopes have half lives that are less than 24 hours and the majority less than 1 minute Chromium also has two metastable nuclear isomers 19 53Cr is the radiogenic decay product of 53Mn half life 3 74 million years 20 Chromium isotopes are typically collocated and compounded with manganese isotopes This circumstance is useful in isotope geology Manganese chromium isotope ratios reinforce the evidence from 26Al and 107Pd concerning the early history of the Solar System Variations in 53Cr 52Cr and Mn Cr ratios from several meteorites indicate an initial 53Mn 55Mn ratio that suggests Mn Cr isotopic composition must result from in situ decay of 53Mn in differentiated planetary bodies Hence 53Cr provides additional evidence for nucleosynthetic processes immediately before coalescence of the Solar System 21 The isotopes of chromium range in atomic mass from 43 u 43Cr to 67 u 67Cr The primary decay mode before the most abundant stable isotope 52Cr is electron capture and the primary mode after is beta decay 19 53Cr has been posited as a proxy for atmospheric oxygen concentration 22 Chemistry and compounds EditSee also Category Chromium compounds The Pourbaix diagram for chromium in pure water perchloric acid or sodium hydroxide 23 24 Chromium is a member of group 6 of the transition metals The 3 and 6 states occur most commonly within chromium compounds followed by 2 charges of 1 4 and 5 for chromium are rare but do nevertheless occasionally exist 25 26 Common oxidation states Edit Oxidation states note 2 26 4 d10 Na4 Cr CO 4 27 2 d8 Na2 Cr CO 5 1 d7 Na2 Cr2 CO 10 0 d6 Cr C6 H6 2 1 d5 K3 Cr CN 5 NO 2 d4 CrCl2 3 d3 CrCl3 4 d2 K2 CrF6 5 d1 K3 Cr O2 4 6 d0 K2 CrO4Chromium 0 Edit Many Cr 0 complexes are known Bis benzene chromium and chromium hexacarbonyl are highlights in organochromium chemistry Chromium II Edit Chromium II carbide Cr3C2 Chromium II compounds are uncommon in part because they readily oxidize to chromium III derivatives in air Water stable chromium II chloride CrCl2 that can be made by reducing chromium III chloride with zinc The resulting bright blue solution created from dissolving chromium II chloride is stable at neutral pH 17 Some other notable chromium II compounds include chromium II oxide CrO and chromium II sulfate CrSO4 Many chromium II carboxylates are known The red chromium II acetate Cr2 O2CCH3 4 is somewhat famous It features a Cr Cr quadruple bond 28 Chromium III Edit Anhydrous chromium III chloride CrCl3 A large number of chromium III compounds are known such as chromium III nitrate chromium III acetate and chromium III oxide 29 Chromium III can be obtained by dissolving elemental chromium in acids like hydrochloric acid or sulfuric acid but it can also be formed through the reduction of chromium VI by cytochrome c7 30 The Cr3 ion has a similar radius 63 pm to Al3 radius 50 pm and they can replace each other in some compounds such as in chrome alum and alum Chromium III tends to form octahedral complexes Commercially available chromium III chloride hydrate is the dark green complex CrCl2 H2O 4 Cl Closely related compounds are the pale green CrCl H2O 5 Cl2 and violet Cr H2O 6 Cl3 If anhydrous violet 31 chromium III chloride is dissolved in water the violet solution turns green after some time as the chloride in the inner coordination sphere is replaced by water This kind of reaction is also observed with solutions of chrome alum and other water soluble chromium III salts A tetrahedral coordination of chromium III has been reported for the Cr centered Keggin anion a CrW12O40 5 32 Chromium III hydroxide Cr OH 3 is amphoteric dissolving in acidic solutions to form Cr H2O 6 3 and in basic solutions to form Cr OH 6 3 It is dehydrated by heating to form the green chromium III oxide Cr2O3 a stable oxide with a crystal structure identical to that of corundum 17 Chromium VI Edit Main article Hexavalent chromium Chromium VI compounds are oxidants at low or neutral pH Chromate anions CrO2 4 and dichromate Cr2O72 anions are the principal ions at this oxidation state They exist at an equilibrium determined by pH 2 CrO4 2 2 H Cr2O7 2 H2OChromium VI oxyhalides are known also and include chromyl fluoride CrO2F2 and chromyl chloride CrO2 Cl2 17 However despite several erroneous claims chromium hexafluoride as well as all higher hexahalides remains unknown as of 2020 33 Chromium VI oxide Sodium chromate is produced industrially by the oxidative roasting of chromite ore with sodium carbonate The change in equilibrium is visible by a change from yellow chromate to orange dichromate such as when an acid is added to a neutral solution of potassium chromate At yet lower pH values further condensation to more complex oxyanions of chromium is possible Both the chromate and dichromate anions are strong oxidizing reagents at low pH 17 Cr2 O2 7 14 H3 O 6 e 2 Cr3 21 H2 O e0 1 33 V They are however only moderately oxidizing at high pH 17 CrO2 4 4 H2 O 3 e Cr OH 3 5 OH e0 0 13 V Sodium chromate Na2CrO4 Chromium VI compounds in solution can be detected by adding an acidic hydrogen peroxide solution The unstable dark blue chromium VI peroxide CrO5 is formed which can be stabilized as an ether adduct CrO5 OR2 17 Chromic acid has the hypothetical formula H2 CrO4 It is a vaguely described chemical despite many well defined chromates and dichromates being known The dark red chromium VI oxide CrO3 the acid anhydride of chromic acid is sold industrially as chromic acid 17 It can be produced by mixing sulfuric acid with dichromate and is a strong oxidizing agent Other oxidation states Edit See also Organochromium chemistry Compounds of chromium V are rather rare the oxidation state 5 is only realized in few compounds but are intermediates in many reactions involving oxidations by chromate The only binary compound is the volatile chromium V fluoride CrF5 This red solid has a melting point of 30 C and a boiling point of 117 C It can be prepared by treating chromium metal with fluorine at 400 C and 200 bar pressure The peroxochromate V is another example of the 5 oxidation state Potassium peroxochromate K3 Cr O2 4 is made by reacting potassium chromate with hydrogen peroxide at low temperatures This red brown compound is stable at room temperature but decomposes spontaneously at 150 170 C 34 Compounds of chromium IV are slightly more common than those of chromium V The tetrahalides CrF4 CrCl4 and CrBr4 can be produced by treating the trihalides CrX3 with the corresponding halogen at elevated temperatures Such compounds are susceptible to disproportionation reactions and are not stable in water Organic compounds containing Cr IV state such as chromium tetra t butoxide are also known 35 Most chromium I compounds are obtained solely by oxidation of electron rich octahedral chromium 0 complexes Other chromium I complexes contain cyclopentadienyl ligands As verified by X ray diffraction a Cr Cr quintuple bond length 183 51 4 pm has also been described 36 Extremely bulky monodentate ligands stabilize this compound by shielding the quintuple bond from further reactions Chromium compound determined experimentally to contain a Cr Cr quintuple bondOccurrence EditSee also Category Chromium minerals Crocoite PbCrO4 Chromite ore Chromium is the 21st 37 most abundant element in Earth s crust with an average concentration of 100 ppm Chromium compounds are found in the environment from the erosion of chromium containing rocks and can be redistributed by volcanic eruptions Typical background concentrations of chromium in environmental media are atmosphere lt 10 ng m3 soil lt 500 mg kg vegetation lt 0 5 mg kg freshwater lt 10 mg L seawater lt 1 mg L sediment lt 80 mg kg 38 Chromium is mined as chromite FeCr2O4 ore 39 About two fifths of the chromite ores and concentrates in the world are produced in South Africa about a third in Kazakhstan 40 while India Russia and Turkey are also substantial producers Untapped chromite deposits are plentiful but geographically concentrated in Kazakhstan and southern Africa 41 Although rare deposits of native chromium exist 42 43 The Udachnaya Pipe in Russia produces samples of the native metal This mine is a kimberlite pipe rich in diamonds and the reducing environment helped produce both elemental chromium and diamonds 44 The relation between Cr III and Cr VI strongly depends on pH and oxidative properties of the location In most cases Cr III is the dominating species 23 but in some areas the ground water can contain up to 39 µg L of total chromium of which 30 µg L is Cr VI 45 History EditEarly applications Edit Chromium minerals as pigments came to the attention of the west in the eighteenth century On 26 July 1761 Johann Gottlob Lehmann found an orange red mineral in the Beryozovskoye mines in the Ural Mountains which he named Siberian red lead 46 47 Though misidentified as a lead compound with selenium and iron components the mineral was in fact crocoite with a formula of PbCrO4 48 In 1770 Peter Simon Pallas visited the same site as Lehmann and found a red lead mineral that was discovered to possess useful properties as a pigment in paints After Pallas the use of Siberian red lead as a paint pigment began to develop rapidly throughout the region 49 Crocoite would be the principal source of chromium in pigments until the discovery of chromite many years later 50 The red color of rubies is due to trace amounts of chromium within the corundum In 1794 Louis Nicolas Vauquelin received samples of crocoite ore He produced chromium trioxide CrO3 by mixing crocoite with hydrochloric acid 48 In 1797 Vauquelin discovered that he could isolate metallic chromium by heating the oxide in a charcoal oven for which he is credited as the one who truly discovered the element 51 52 Vauquelin was also able to detect traces of chromium in precious gemstones such as ruby and emerald 48 53 During the nineteenth century chromium was primarily used not only as a component of paints but in tanning salts as well For quite some time the crocoite found in Russia was the main source for such tanning materials In 1827 a larger chromite deposit was discovered near Baltimore United States which quickly met the demand for tanning salts much more adequately than the crocoite that had been used previously 54 This made the United States the largest producer of chromium products until the year 1848 when larger deposits of chromite were uncovered near the city of Bursa Turkey 39 With the development of metallurgy and chemical industries in the Western world the need for chromium increased 55 Chromium is also famous for its reflective metallic luster when polished It is used as a protective and decorative coating on car parts plumbing fixtures furniture parts and many other items usually applied by electroplating Chromium was used for electroplating as early as 1848 but this use only became widespread with the development of an improved process in 1924 56 Production Edit Piece of chromium produced with aluminothermic reaction World production trend of chromium Chromium remelted in a horizontal arc zone refiner showing large visible crystal grains Approximately 28 8 million metric tons Mt of marketable chromite ore was produced in 2013 and converted into 7 5 Mt of ferrochromium 41 According to John F Papp writing for the USGS Ferrochromium is the leading end use of chromite ore and stainless steel is the leading end use of ferrochromium 41 The largest producers of chromium ore in 2013 have been South Africa 48 Kazakhstan 13 Turkey 11 and India 10 with several other countries producing the rest of about 18 of the world production 41 The two main products of chromium ore refining are ferrochromium and metallic chromium For those products the ore smelter process differs considerably For the production of ferrochromium the chromite ore FeCr2O4 is reduced in large scale in electric arc furnace or in smaller smelters with either aluminium or silicon in an aluminothermic reaction 57 Chromium ore output in 2002 58 For the production of pure chromium the iron must be separated from the chromium in a two step roasting and leaching process The chromite ore is heated with a mixture of calcium carbonate and sodium carbonate in the presence of air The chromium is oxidized to the hexavalent form while the iron forms the stable Fe2O3 The subsequent leaching at higher elevated temperatures dissolves the chromates and leaves the insoluble iron oxide The chromate is converted by sulfuric acid into the dichromate 57 4 FeCr2O4 8 Na2CO3 7 O2 8 Na2CrO4 2 Fe2O3 8 CO22 Na2CrO4 H2SO4 Na2Cr2O7 Na2SO4 H2OThe dichromate is converted to the chromium III oxide by reduction with carbon and then reduced in an aluminothermic reaction to chromium 57 Na2Cr2O7 2 C Cr2O3 Na2CO3 CO Cr2O3 2 Al Al2O3 2 CrApplications EditThe creation of metal alloys account for 85 of the available chromium s usage The remainder of chromium is used in the chemical refractory and foundry industries 59 Metallurgy Edit Stainless steel cutlery made from Cromargan 18 10 containing 18 chromium Main articles Chrome plating and Stainless steel The strengthening effect of forming stable metal carbides at grain boundaries and the strong increase in corrosion resistance made chromium an important alloying material for steel High speed tool steels contain between 3 and 5 chromium Stainless steel the primary corrosion resistant metal alloy is formed when chromium is introduced to iron in concentrations above 11 60 For stainless steel s formation ferrochromium is added to the molten iron Also nickel based alloys have increased strength due to the formation of discrete stable metal carbide particles at the grain boundaries For example Inconel 718 contains 18 6 chromium Because of the excellent high temperature properties of these nickel superalloys they are used in jet engines and gas turbines in lieu of common structural materials 61 ASTM B163 relies on Chromium for condenser and heat exchanger tubes while castings with high strength at elevated temperatures that contain Chromium are standardised with ASTM A567 62 AISI type 332 is used where high temperature would normally cause carburization oxidation or corrosion 63 Incoloy 800 is capable of remaining stable and maintaining its austenitic structure even after long time exposures to high temperatures 64 Nichrome is used as resistance wire for heating elements in things like toasters and space heaters These uses make chromium a strategic material Consequently during World War II U S road engineers were instructed to avoid chromium in yellow road paint as it may become a critical material during the emergency 65 The United States likewise considered chromium essential for the German war industry and made intense diplomatic efforts to keep it out of the hands of Nazi Germany 66 Decorative chrome plating on a motorcycle The high hardness and corrosion resistance of unalloyed chromium makes it a reliable metal for surface coating it is still the most popular metal for sheet coating with its above average durability compared to other coating metals 67 A layer of chromium is deposited on pretreated metallic surfaces by electroplating techniques There are two deposition methods thin and thick Thin deposition involves a layer of chromium below 1 µm thickness deposited by chrome plating and is used for decorative surfaces Thicker chromium layers are deposited if wear resistant surfaces are needed Both methods use acidic chromate or dichromate solutions To prevent the energy consuming change in oxidation state the use of chromium III sulfate is under development for most applications of chromium the previously established process is used 56 In the chromate conversion coating process the strong oxidative properties of chromates are used to deposit a protective oxide layer on metals like aluminium zinc and cadmium This passivation and the self healing properties of the chromate stored in the chromate conversion coating which is able to migrate to local defects are the benefits of this coating method 68 Because of environmental and health regulations on chromates alternative coating methods are under development 69 Chromic acid anodizing or Type I anodizing of aluminium is another electrochemical process that does not lead to the deposition of chromium but uses chromic acid as an electrolyte in the solution During anodization an oxide layer is formed on the aluminium The use of chromic acid instead of the normally used sulfuric acid leads to a slight difference of these oxide layers 70 The high toxicity of Cr VI compounds used in the established chromium electroplating process and the strengthening of safety and environmental regulations demand a search for substitutes for chromium or at least a change to less toxic chromium III compounds 56 Pigment Edit The mineral crocoite which is also lead chromate PbCrO4 was used as a yellow pigment shortly after its discovery After a synthesis method became available starting from the more abundant chromite chrome yellow was together with cadmium yellow one of the most used yellow pigments The pigment does not photodegrade but it tends to darken due to the formation of chromium III oxide It has a strong color and was used for school buses in the United States and for the postal services for example the Deutsche Post in Europe The use of chrome yellow has since declined due to environmental and safety concerns and was replaced by organic pigments or other alternatives that are free from lead and chromium Other pigments that are based around chromium are for example the deep shade of red pigment chrome red which is simply lead chromate with lead II hydroxide PbCrO4 Pb OH 2 A very important chromate pigment which was used widely in metal primer formulations was zinc chromate now replaced by zinc phosphate A wash primer was formulated to replace the dangerous practice of pre treating aluminium aircraft bodies with a phosphoric acid solution This used zinc tetroxychromate dispersed in a solution of polyvinyl butyral An 8 solution of phosphoric acid in solvent was added just before application It was found that an easily oxidized alcohol was an essential ingredient A thin layer of about 10 15 µm was applied which turned from yellow to dark green when it was cured There is still a question as to the correct mechanism Chrome green is a mixture of Prussian blue and chrome yellow while the chrome oxide green is chromium III oxide 71 Chromium oxides are also used as a green pigment in the field of glassmaking and also as a glaze for ceramics 72 Green chromium oxide is extremely lightfast and as such is used in cladding coatings It is also the main ingredient in infrared reflecting paints used by the armed forces to paint vehicles and to give them the same infrared reflectance as green leaves 73 Other uses Edit Red crystal of a ruby laser Chromium III ions present in corundum crystals aluminium oxide cause them to be colored red when corundum appears as such it is known as a ruby If the corundum is lacking in chromium III ions it is known as a sapphire note 3 A red colored artificial ruby may also be achieved by doping chromium III into artificial corundum crystals thus making chromium a requirement for making synthetic rubies note 4 74 Such a synthetic ruby crystal was the basis for the first laser produced in 1960 which relied on stimulated emission of light from the chromium atoms in such a crystal Ruby has a laser transition at 694 3 nanometers in a deep red color 75 Because of their toxicity chromium VI salts are used for the preservation of wood For example chromated copper arsenate CCA is used in timber treatment to protect wood from decay fungi wood attacking insects including termites and marine borers 76 The formulations contain chromium based on the oxide CrO3 between 35 3 and 65 5 In the United States 65 300 metric tons of CCA solution were used in 1996 76 Chromium III salts especially chrome alum and chromium III sulfate are used in the tanning of leather The chromium III stabilizes the leather by cross linking the collagen fibers 77 Chromium tanned leather can contain between 4 and 5 of chromium which is tightly bound to the proteins 39 Although the form of chromium used for tanning is not the toxic hexavalent variety there remains interest in management of chromium in the tanning industry Recovery and reuse direct indirect recycling 78 and chrome less or chrome free tanning are practiced to better manage chromium usage 79 The high heat resistivity and high melting point makes chromite and chromium III oxide a material for high temperature refractory applications like blast furnaces cement kilns molds for the firing of bricks and as foundry sands for the casting of metals In these applications the refractory materials are made from mixtures of chromite and magnesite The use is declining because of the environmental regulations due to the possibility of the formation of chromium VI 57 80 Several chromium compounds are used as catalysts for processing hydrocarbons For example the Phillips catalyst prepared from chromium oxides is used for the production of about half the world s polyethylene 81 Fe Cr mixed oxides are employed as high temperature catalysts for the water gas shift reaction 82 83 Copper chromite is a useful hydrogenation catalyst 84 Chromates of metals are used in humistor 85 Uses of compounds Edit Chromium IV oxide CrO2 is a magnetic compound Its ideal shape anisotropy which imparts high coercivity and remnant magnetization made it a compound superior to g Fe2O3 Chromium IV oxide is used to manufacture magnetic tape used in high performance audio tape and standard audio cassettes 86 Chromium III oxide Cr2O3 is a metal polish known as green rouge 87 88 Chromic acid is a powerful oxidizing agent and is a useful compound for cleaning laboratory glassware of any trace of organic compounds 89 It is prepared by dissolving potassium dichromate in concentrated sulfuric acid which is then used to wash the apparatus Sodium dichromate is sometimes used because of its higher solubility 50 g L versus 200 g L respectively The use of dichromate cleaning solutions is now phased out due to the high toxicity and environmental concerns Modern cleaning solutions are highly effective and chromium free 90 Potassium dichromate is a chemical reagent used as a titrating agent 91 Chromates are added to drilling muds to prevent corrosion of steel under wet conditions 92 Chrome alum is Chromium III potassium sulfate and is used as a mordant i e a fixing agent for dyes in fabric and in tanning 93 Biological role EditSee also Chromium in glucose metabolism The biologically beneficial effects of chromium III are debated 94 95 Chromium is accepted by the U S National Institutes of Health as a trace element for its roles in the action of insulin a hormone that mediates the metabolism and storage of carbohydrate fat and protein 7 The mechanism of its actions in the body however have not been defined leaving in question the essentiality of chromium 96 97 In contrast hexavalent chromium Cr VI or Cr6 is highly toxic and mutagenic 98 Ingestion of chromium VI in water has been linked to stomach tumors and it may also cause allergic contact dermatitis ACD 99 Chromium deficiency involving a lack of Cr III in the body or perhaps some complex of it such as glucose tolerance factor is controversial 7 Some studies suggest that the biologically active form of chromium III is transported in the body via an oligopeptide called low molecular weight chromium binding substance LMWCr which might play a role in the insulin signaling pathway 100 The chromium content of common foods is generally low 1 13 micrograms per serving 7 101 The chromium content of food varies widely due to differences in soil mineral content growing season plant cultivar and contamination during processing 101 Chromium and nickel leach into food cooked in stainless steel with the effect being largest when the cookware is new Acidic foods that are cooked for many hours also exacerbate this effect 102 103 Dietary recommendations Edit See also Chromium deficiency There is disagreement on chromium s status as an essential nutrient Governmental departments from Australia New Zealand India Japan and the United States consider chromium essential 104 105 106 107 while the European Food Safety Authority EFSA of the European Union does not 108 The U S National Academy of Medicine NAM updated the Estimated Average Requirements EARs and the Recommended Dietary Allowances RDAs for chromium in 2001 For chromium there was insufficient information to set EARs and RDAs so its needs are described as estimates for Adequate Intakes AIs The current AIs of chromium for women ages 14 through 50 is 25 mg day and the AIs for women ages 50 and above is 20 mg day The AIs for women who are pregnant are 30 mg day and for women who are lactating the set AIs are 45 mg day The AIs for men ages 14 through 50 are 35 mg day and the AIs for men ages 50 and above are 30 mg day For children ages 1 through 13 the AIs increase with age from 0 2 mg day up to 25 mg day As for safety the NAM sets Tolerable Upper Intake Levels ULs for vitamins and minerals when the evidence is sufficient In the case of chromium there is not yet enough information hence no UL has been established Collectively the EARs RDAs AIs and ULs are the parameters for the nutrition recommendation system known as Dietary Reference Intake DRI 107 Australia and New Zealand consider chromium to be an essential nutrient with an AI of 35 mg day for men 25 mg day for women 30 mg day for women who are pregnant and 45 mg day for women who are lactating A UL has not been set due to the lack of sufficient data 104 India considers chromium to be an essential nutrient with an adult recommended intake of 33 mg day 105 Japan also considers chromium to be an essential nutrient with an AI of 10 mg day for adults including women who are pregnant or lactating A UL has not been set 106 The EFSA of the European Union however does not consider chromium to be an essential nutrient chromium is the only mineral for which the United States and the European Union disagree 108 109 Labeling Edit For U S food and dietary supplement labeling purposes the amount of the substance in a serving is expressed as a percent of the Daily Value DV For chromium labeling purposes 100 of the Daily Value was 120 mg As of May 27 2016 the percentage of daily value was revised to 35 mg to bring the chromium intake into a consensus with the official Recommended Dietary Allowance 110 111 A table of the old and new adult daily values is provided at Reference Daily Intake Food sources Edit Food composition databases such as those maintained by the U S Department of Agriculture do not contain information on the chromium content of foods 112 A wide variety of animal and vegetable foods contain chromium 107 Content per serving is influenced by the chromium content of the soil in which the plants are grown by foodstuffs fed to animals and by processing methods as chromium is leached into foods if processed or cooked in stainless steel equipment 113 One diet analysis study conducted in Mexico reported an average daily chromium intake of 30 micrograms 114 An estimated 31 of adults in the United States consume multi vitamin mineral dietary supplements 115 which often contain 25 to 60 micrograms of chromium Supplementation Edit Chromium is an ingredient in total parenteral nutrition TPN because deficiency can occur after months of intravenous feeding with chromium free TPN 116 It is also added to nutritional products for preterm infants 117 Although the mechanism of action in biological roles for chromium is unclear in the United States chromium containing products are sold as non prescription dietary supplements in amounts ranging from 50 to 1 000 mg Lower amounts of chromium are also often incorporated into multi vitamin mineral supplements consumed by an estimated 31 of adults in the United States 115 Chemical compounds used in dietary supplements include chromium chloride chromium citrate chromium III picolinate chromium III polynicotinate and other chemical compositions 7 The benefit of supplements has not been proven 7 118 Approved and disapproved health claims Edit In 2005 the U S Food and Drug Administration had approved a qualified health claim for chromium picolinate with a requirement for very specific label wording One small study suggests that chromium picolinate may reduce the risk of insulin resistance and therefore possibly may reduce the risk of type 2 diabetes FDA concludes however that the existence of such a relationship between chromium picolinate and either insulin resistance or type 2 diabetes is highly uncertain At the same time in answer to other parts of the petition the FDA rejected claims for chromium picolinate and cardiovascular disease retinopathy or kidney disease caused by abnormally high blood sugar levels 119 In 2010 chromium III picolinate was approved by Health Canada to be used in dietary supplements Approved labeling statements include a factor in the maintenance of good health provides support for healthy glucose metabolism helps the body to metabolize carbohydrates and helps the body to metabolize fats 120 The European Food Safety Authority EFSA approved claims in 2010 that chromium contributed to normal macronutrient metabolism and maintenance of normal blood glucose concentration but rejected claims for maintenance or achievement of a normal body weight or reduction of tiredness or fatigue 121 Given the evidence for chromium deficiency causing problems with glucose management in the context of intravenous nutrition products formulated without chromium 116 research interest turned to whether chromium supplementation would benefit people who have type 2 diabetes but are not chromium deficient Looking at the results from four meta analyses one reported a statistically significant decrease in fasting plasma glucose levels FPG and a non significant trend in lower hemoglobin A1C 122 A second reported the same 123 a third reported significant decreases for both measures 124 while a fourth reported no benefit for either 125 A review published in 2016 listed 53 randomized clinical trials that were included in one or more of six meta analyses It concluded that whereas there may be modest decreases in FPG and or HbA1C that achieve statistical significance in some of these meta analyses few of the trials achieved decreases large enough to be expected to be relevant to clinical outcome 126 Two systematic reviews looked at chromium supplements as a mean of managing body weight in overweight and obese people One limited to chromium picolinate a popular supplement ingredient reported a statistically significant 1 1 kg 2 4 lb weight loss in trials longer than 12 weeks 127 The other included all chromium compounds and reported a statistically significant 0 50 kg 1 1 lb weight change 128 Change in percent body fat did not reach statistical significance Authors of both reviews considered the clinical relevance of this modest weight loss as uncertain unreliable 127 128 The European Food Safety Authority reviewed the literature and concluded that there was insufficient evidence to support a claim 121 Chromium is promoted as a sports performance dietary supplement based on the theory that it potentiates insulin activity with anticipated results of increased muscle mass and faster recovery of glycogen storage during post exercise recovery 118 129 130 A review of clinical trials reported that chromium supplementation did not improve exercise performance or increase muscle strength 131 The International Olympic Committee reviewed dietary supplements for high performance athletes in 2018 and concluded there was no need to increase chromium intake for athletes nor support for claims of losing body fat 132 Fresh water fish Edit Chromium is naturally present in the environment in trace amounts but industrial use in rubber and stainless steel manufacturing chrome plating dyes for textiles tanneries and other uses contaminates aquatic systems In Bangladesh rivers in or downstream from industrialized areas exhibit heavy metal contamination Irrigation water standards for chromium are 0 1 mg L but some rivers are more than five times that amount The standard for fish for human consumption is less than 1 mg kg but many tested samples were more than five times that amount 133 Chromium especially hexavalent chromium is highly toxic to fish because it is easily absorbed across the gills readily enters blood circulation crosses cell membranes and bioconcentrates up the food chain In contrast the toxicity of trivalent chromium is very low attributed to poor membrane permeability and little biomagnification 134 Acute and chronic exposure to chromium VI affects fish behavior physiology reproduction and survival Hyperactivity and erratic swimming have been reported in contaminated environments Egg hatching and fingerling survival are affected In adult fish there are reports of histopathological damage to liver kidney muscle intestines and gills Mechanisms include mutagenic gene damage and disruptions of enzyme functions 134 There is evidence that fish may not require chromium but benefit from a measured amount in diet In one study juvenile fish gained weight on a zero chromium diet but the addition of 500 mg of chromium in the form of chromium chloride or other supplement types per kilogram of food dry weight increased weight gain At 2 000 mg kg the weight gain was no better than with the zero chromium diet and there were increased DNA strand breaks 135 Precautions EditMain article Chromium toxicity Water insoluble chromium III compounds and chromium metal are not considered a health hazard while the toxicity and carcinogenic properties of chromium VI have been known for a long time 136 Because of the specific transport mechanisms only limited amounts of chromium III enter the cells Acute oral toxicity ranges between 50 and 150 mg kg 137 A 2008 review suggested that moderate uptake of chromium III through dietary supplements poses no genetic toxic risk 138 In the US the Occupational Safety and Health Administration OSHA has designated an air permissible exposure limit PEL in the workplace as a time weighted average TWA of 1 mg m3 The National Institute for Occupational Safety and Health NIOSH has set a recommended exposure limit REL of 0 5 mg m3 time weighted average The IDLH immediately dangerous to life and health value is 250 mg m3 139 Chromium VI toxicity Edit The acute oral toxicity for chromium VI ranges between 1 5 and 3 3 mg kg 137 In the body chromium VI is reduced by several mechanisms to chromium III already in the blood before it enters the cells The chromium III is excreted from the body whereas the chromate ion is transferred into the cell by a transport mechanism by which also sulfate and phosphate ions enter the cell The acute toxicity of chromium VI is due to its strong oxidant properties After it reaches the blood stream it damages the kidneys the liver and blood cells through oxidation reactions Hemolysis renal and liver failure result Aggressive dialysis can be therapeutic 140 The carcinogenity of chromate dust has been known for a long time and in 1890 the first publication described the elevated cancer risk of workers in a chromate dye company 141 142 Three mechanisms have been proposed to describe the genotoxicity of chromium VI The first mechanism includes highly reactive hydroxyl radicals and other reactive radicals which are by products of the reduction of chromium VI to chromium III The second process includes the direct binding of chromium V produced by reduction in the cell and chromium IV compounds to the DNA The last mechanism attributed the genotoxicity to the binding to the DNA of the end product of the chromium III reduction 143 144 Chromium salts chromates are also the cause of allergic reactions in some people Chromates are often used to manufacture amongst other things leather products paints cement mortar and anti corrosives Contact with products containing chromates can lead to allergic contact dermatitis and irritant dermatitis resulting in ulceration of the skin sometimes referred to as chrome ulcers This condition is often found in workers that have been exposed to strong chromate solutions in electroplating tanning and chrome producing manufacturers 145 146 Environmental issues Edit Because chromium compounds were used in dyes paints and leather tanning compounds these compounds are often found in soil and groundwater at active and abandoned industrial sites needing environmental cleanup and remediation Primer paint containing hexavalent chromium is still widely used for aerospace and automobile refinishing applications 147 In 2010 the Environmental Working Group studied the drinking water in 35 American cities in the first nationwide study The study found measurable hexavalent chromium in the tap water of 31 of the cities sampled with Norman Oklahoma at the top of list 25 cities had levels that exceeded California s proposed limit 148 The more toxic hexavalent chromium form can be reduced to the less soluble trivalent oxidation state in soils by organic matter ferrous iron sulfides and other reducing agents with the rates of such reduction being faster under more acidic conditions than under more alkaline ones In contrast trivalent chromium can be oxidized to hexavalent chromium in soils by manganese oxides such as Mn III and Mn IV compounds Since the solubility and toxicity of chromium VI are greater that those of chromium III the oxidation reduction conversions between the two oxidation states have implications for movement and bioavailability of chromium in soils groundwater and plants 149 Notes Edit The melting boiling point of transition metals are usually higher compared to the alkali metals alkaline earth metals and nonmetals which is why the range of elements compared to chromium differed between comparisons Most common oxidation states of chromium are in bold The right column lists a representative compound for each oxidation state Any color of corundum disregarding red is known as a sapphire If the corundum is red then it is a ruby Sapphires are not required to be blue corundum crystals as sapphires can be other colors such as yellow and purple When Cr3 replaces Al3 in corundum aluminium oxide Al2O3 pink sapphire or ruby is formed depending on the amount of chromium References Edit Standard Atomic Weights Chromium CIAAW 1983 a b Fawcett Eric 1988 Spin density wave antiferromagnetism in chromium Reviews of Modern Physics 60 209 Bibcode 1988RvMP 60 209F doi 10 1103 RevModPhys 60 209 Weast Robert 1984 CRC Handbook of Chemistry and Physics Boca Raton Florida Chemical Rubber Company Publishing pp E110 ISBN 0 8493 0464 4 Brandes EA Greenaway HT Stone HEN 1956 Ductility in Chromium Nature 178 4533 587 Bibcode 1956Natur 178 587B doi 10 1038 178587a0 S2CID 4221048 a b c Coblentz WW Stair R Reflecting power of beryllium chromium and several other metals PDF National Institute of Standards and Technology NIST Publications Retrieved 11 October 2018 xrῶma Henry George Liddell Robert Scott A Greek English Lexicon on Perseus a b c d e f Chromium Office of Dietary Supplements US National Institutes of Health 2016 Retrieved 26 June 2016 Scientific Opinion on Dietary Reference Values for chromium European Food Safety Authority 18 September 2014 Retrieved 20 March 2018 Substance Information ECHA echa europa eu Retrieved 17 January 2022 EPA August 2000 Abandoned Mine Site Characterization and Cleanup Handbook PDF United States Environmental Protection Agency Retrieved 8 September 2019 The Nature of X Ray Photoelectron Spectra CasaXPS Casa Software Ltd 2005 Retrieved 10 March 2019 Schwarz W H Eugen April 2010 The Full Story of the Electron Configurations of the Transition Elements PDF Journal of Chemical Education 87 4 444 8 Bibcode 2010JChEd 87 444S doi 10 1021 ed8001286 Retrieved 9 November 2018 Greenwood and Earnshaw pp 1004 5 a b Lind Michael Acton 1972 The infrared reflectivity of chromium and chromium aluminium alloys Iowa State University Digital Repository Iowa State University Bibcode 1972PhDT 54L Retrieved 4 November 2018 Bos Laurence William 1969 Optical properties of chromium manganese alloys Iowa State University Digital Repository Iowa State University Bibcode 1969PhDT 118B Retrieved 4 November 2018 Wallwork GR 1976 The oxidation of alloys Reports on Progress in Physics 39 5 401 485 Bibcode 1976RPPh 39 401W doi 10 1088 0034 4885 39 5 001 S2CID 250853920 a b c d e f g h Holleman Arnold F Wiber Egon Wiberg Nils 1985 Chromium Lehrbuch der Anorganischen Chemie in German 91 100 ed Walter de Gruyter pp 1081 1095 ISBN 978 3 11 007511 3 National Research Council U S Committee on Coatings 1970 High temperature oxidation resistant coatings coatings for protection from oxidation of superalloys refractory metals and graphite National Academy of Sciences ISBN 978 0 309 01769 5 a b Kondev F G Wang M Huang W J Naimi S Audi G 2021 The NUBASE2020 evaluation of nuclear properties PDF Chinese Physics C 45 3 030001 doi 10 1088 1674 1137 abddae Live Chart of Nuclides International Atomic Energy Agency Nuclear Data Section Retrieved 18 October 2018 Birck JL Rotaru M Allegre C 1999 53Mn 53Cr evolution of the early solar system Geochimica et Cosmochimica Acta 63 23 24 4111 4117 Bibcode 1999GeCoA 63 4111B doi 10 1016 S0016 7037 99 00312 9 Frei Robert Gaucher Claudio Poulton Simon W Canfield Don E 2009 Fluctuations in Precambrian atmospheric oxygenation recorded by chromium isotopes Nature 461 7261 250 253 Bibcode 2009Natur 461 250F doi 10 1038 nature08266 PMID 19741707 S2CID 4373201 a b Kotas J Stasicka Z 2000 Chromium occurrence in the environment and methods of its speciation Environmental Pollution 107 3 263 283 doi 10 1016 S0269 7491 99 00168 2 PMID 15092973 Puigdomenech Ignasi Hydra Medusa Chemical Equilibrium Database and Plotting Software Archived 5 June 2013 at the Wayback Machine 2004 KTH Royal Institute of Technology Clark Jim Oxidation states oxidation numbers Chemguide Retrieved 3 October 2018 a b Greenwood Norman N Earnshaw Alan 1997 Chemistry of the Elements 2nd ed Butterworth Heinemann ISBN 978 0 08 037941 8 Theopold Klaus H Kucharczyk Robin R 15 December 2011 Chromium Organometallic Chemistry in Scott Robert A ed Encyclopedia of Inorganic and Bioinorganic Chemistry John Wiley amp Sons Ltd pp eibc0042 doi 10 1002 9781119951438 eibc0042 ISBN 978 1 119 95143 8 Cotton FA Walton RA 1993 Multiple Bonds Between Metal Atoms Oxford Oxford University Press ISBN 978 0 19 855649 7 Chromium III compounds National Pollutant Inventory Commonwealth of Australia Retrieved 8 November 2018 Assfalg M Banci L Bertini I Bruschi M Michel C Giudici Orticoni M Turano P 31 July 2002 NMR structural characterization of the reduction of chromium VI to chromium III by cytochrome c7 Protein Data Bank 1LM2 doi 10 2210 pdb1LM2 pdb Retrieved 8 November 2018 Luther George W 2016 Introduction to Transition Metals Inorganic Chemistry for Geochemistry amp Environmental Sciences Fundamentals amp Applications Hydrate Solvate Isomers John Wiley amp Sons p 244 ISBN 978 1118851371 Retrieved 7 August 2019 Gumerova Nadiia I Roller Alexander Giester Gerald Krzystek J Cano Joan Rompel Annette 19 February 2020 Incorporation of CrIII into a Keggin Polyoxometalate as a Chemical Strategy to Stabilize a Labile CrIIIO4 Tetrahedral Conformation and Promote Unattended Single Ion Magnet Properties Journal of the American Chemical Society 142 7 3336 3339 doi 10 1021 jacs 9b12797 ISSN 0002 7863 PMC 7052816 PMID 31967803 Seppelt Konrad 28 January 2015 Molecular Hexafluorides Chemical Reviews 115 2 1296 1306 doi 10 1021 cr5001783 ISSN 0009 2665 PMID 25418862 Haxhillazi Gentiana 2003 Preparation Structure and Vibrational Spectroscopy of Tetraperoxo Complexes of CrV VV NbV and TaV PhD thesis University of Siegen Thaler Eric G Rypdal Kristin Haaland Arne Caulton Kenneth G 1 June 1989 Structure and reactivity of chromium 4 tert butoxide Inorganic Chemistry 28 12 2431 2434 doi 10 1021 ic00311a035 ISSN 0020 1669 Nguyen T Sutton AD Brynda M Fettinger JC Long GJ Power PP 2005 Synthesis of a stable compound with fivefold bonding between two chromium I centers Science 310 5749 844 847 Bibcode 2005Sci 310 844N doi 10 1126 science 1116789 PMID 16179432 S2CID 42853922 Emsley John 2001 Chromium Nature s Building Blocks An A Z Guide to the Elements Oxford England UK Oxford University Press pp 495 498 ISBN 978 0 19 850340 8 John Rieuwerts 14 July 2017 The Elements of Environmental Pollution Taylor amp Francis ISBN 978 1 135 12679 7 a b c National Research Council U S Committee on Biologic Effects of Atmospheric Pollutants 1974 Chromium National Academy of Sciences ISBN 978 0 309 02217 0 Champion Marc 11 January 2018 How a Trump SoHo Partner Ended Up With Toxic Mining Riches From Kazakhstan Bloomberg com Bloomberg L P Retrieved 21 January 2018 a b c d Papp John F Mineral Yearbook 2015 Chromium PDF United States Geological Survey Retrieved 3 June 2015 Fleischer Michael 1982 New Mineral Names PDF American Mineralogist 67 854 860 Chromium with location data Mindat Chromium from Udachnaya Vostochnaya pipe Daldyn Daldyn Alakit kimberlite field Saha Republic Sakha Republic Yakutia Eastern Siberian Region Russia Mindat Gonzalez A R Ndung u K Flegal A R 2005 Natural Occurrence of Hexavalent Chromium in the Aromas Red Sands Aquifer California Environmental Science and Technology 39 15 5505 5511 Bibcode 2005EnST 39 5505G doi 10 1021 es048835n PMID 16124280 Meyer RJ 1962 Chrom Teil A Lieferung 1 Geschichtliches Vorkommen Technologie Element bis Physikalische Eigenschaften in German Berlin Heidelberg Springer Berlin Heidelberg Imprint Springer ISBN 978 3 662 11865 8 OCLC 913810356 Lehmanni Iohannis Gottlob 1766 De Nova Minerae Plumbi Specie Crystallina Rubra Epistola a b c Guertin Jacques Jacobs James Alan amp Avakian Cynthia P 2005 Chromium VI Handbook CRC Press pp 7 11 ISBN 978 1 56670 608 7 Weeks Mary Elvira 1932 The discovery of the elements V Chromium molybdenum tungsten and uranium Journal of Chemical Education 9 3 459 73 Bibcode 1932JChEd 9 459W doi 10 1021 ed009p459 ISSN 0021 9584 Casteran Rene Chromite mining Oregon Encyclopedia Portland State University and the Oregon Historical Society Retrieved 1 October 2018 Vauquelin Louis Nicolas 1798 Memoir on a New Metallic Acid which exists in the Red Lead of Siberia Journal of Natural Philosophy Chemistry and the Arts 3 145 146 Glenn William 1895 Chrome in the Southern Appalachian Region Transactions of the American Institute of Mining Metallurgical and Petroleum Engineers 25 482 van der Krogt Peter Chromium Retrieved 24 August 2008 Ortt Richard A Jr Soldier s Delight Baltimore Country Maryland Department of Natural Resources Maryland Geological Survey Retrieved 13 May 2019 Bilgin Arif Caglar Burhan eds Klasikten Moderne Osmanli Ekonomisi Turkey Kronik Kitap p 240 a b c Dennis JK Such TE 1993 History of Chromium Plating Nickel and Chromium Plating Woodhead Publishing pp 9 12 ISBN 978 1 85573 081 6 a b c d Papp John F amp Lipin Bruce R 2006 Chromite Industrial Minerals amp Rocks Commodities Markets and Uses 7th ed SME ISBN 978 0 87335 233 8 Papp John F Mineral Yearbook 2002 Chromium PDF United States Geological Survey Retrieved 16 February 2009 Morrison RD Murphy BL 4 August 2010 Environmental Forensics Contaminant Specific Guide Academic Press ISBN 9780080494784 Davis JR 2000 Alloy digest sourcebook stainless steels in Afrikaans Materials Park OH ASM International pp 1 5 ISBN 978 0 87170 649 2 OCLC 43083287 Bhadeshia HK Nickel Based Superalloys University of Cambridge Archived from the original on 25 August 2006 Retrieved 17 February 2009 Chromium Nickel and Welding IARC Monographs International Agency for Research on Cancer 49 49 50 1990 Stainless Steel Grade 332 UNS S33200 AZoNetwork 5 March 2013 Super Alloy INCOLOY Alloy 800 UNS N08800 AZoNetwork 3 July 2013 Manual On Uniform Traffic Control Devices War Emergency Edition PDF Washington DC American Associan of State Highway Officials November 1942 p 52 Retrieved 8 July 2021 State Department United States Allied Relations and Negotiations with Turkey PDF Archived PDF from the original on 9 November 2020 Breitsameter M 15 August 2002 Thermal Spraying versus Hard Chrome Plating Azo Materials AZoNetwork Retrieved 1 October 2018 Edwards J 1997 Coating and Surface Treatment Systems for Metals Finishing Publications Ltd and ASMy International pp 66 71 ISBN 978 0 904477 16 0 Zhao J Xia L Sehgal A Lu D McCreery RL Frankel GS 2001 Effects of chromate and chromate conversion coatings on corrosion of aluminum alloy 2024 T3 Surface and Coatings Technology 140 1 51 57 doi 10 1016 S0257 8972 01 01003 9 hdl 1811 36519 Cotell CM Sprague JA Smidt FA 1994 ASM Handbook Surface Engineering ASM International ISBN 978 0 87170 384 2 Retrieved 17 February 2009 Gettens Rutherford John 1966 Chrome yellow Painting Materials A Short Encyclopaedia Courier Dover Publications pp 105 106 ISBN 978 0 486 21597 6 Gerd Anger et al Chromium Compounds Ullmann s Encyclopedia of Industrial Chemistry 2005 Wiley VCH Weinheim doi 10 1002 14356007 a07 067 Marrion Alastair 2004 The chemistry and physics of coatings Royal Society of Chemistry pp 287 ISBN 978 0 85404 604 1 Moss SC Newnham RE 1964 The chromium position in ruby PDF Zeitschrift fur Kristallographie 120 4 5 359 363 Bibcode 1964ZK 120 359M doi 10 1524 zkri 1964 120 4 5 359 Webb Colin E Jones Julian DC 2004 Handbook of Laser Technology and Applications Laser design and laser systems CRC Press pp 323 ISBN 978 0 7503 0963 9 a b Hingston J Collins CD Murphy RJ Lester JN 2001 Leaching of chromated copper arsenate wood preservatives a review Environmental Pollution 111 1 53 66 doi 10 1016 S0269 7491 00 00030 0 PMID 11202715 Brown EM 1997 A Conformational Study of Collagen as Affected by Tanning Procedures Journal of the American Leather Chemists Association 92 225 233 Sreeram K Ramasami T 2003 Sustaining tanning process through conservation recovery and better utilization of chromium Resources Conservation and Recycling 38 3 185 212 doi 10 1016 S0921 3449 02 00151 9 Qiang Taotao Gao Xin Ren Jing Chen Xiaoke Wang Xuechuan 9 December 2015 A Chrome Free and Chrome Less Tanning System Based on the Hyperbranched Polymer ACS Sustainable Chemistry amp Engineering 4 3 701 707 doi 10 1021 acssuschemeng 5b00917 Barnhart Joel 1997 Occurrences Uses and Properties of Chromium Regulatory Toxicology and Pharmacology 26 1 S3 S7 doi 10 1006 rtph 1997 1132 ISSN 0273 2300 PMID 9380835 Weckhuysen Bert M Schoonheydt Robert A 1999 Olefin polymerization over supported chromium oxide catalysts PDF Catalysis Today 51 2 215 221 doi 10 1016 S0920 5861 99 00046 2 hdl 1874 21357 S2CID 98324455 Twigg MVE 1989 The Water Gas Shift Reaction Catalyst Handbook ISBN 978 0 7234 0857 4 Rhodes C Hutchings GJ Ward AM 1995 Water gas shift reaction Finding the mechanistic boundary Catalysis Today 23 43 58 doi 10 1016 0920 5861 94 00135 O Lazier WA amp Arnold HR 1939 Copper Chromite Catalyst Organic Syntheses 19 31 Collective Volume vol 2 p 142 Kitagawa Hiraku April 1989 Li Te and Ca Te thin film junctions as humidity sensors Sensors and Actuators 16 4 369 378 doi 10 1016 0250 6874 89 85007 3 Mallinson John C 1993 Chromium Dioxide The foundations of magnetic recording Academic Press p 32 ISBN 978 0 12 466626 9 Toshiro Doi Ioan D Marinescu Syuhei Kurokawa 30 November 2011 Advances in CMP Polishing Technologies William Andrew pp 60 ISBN 978 1 4377 7860 1 Baral Anil Engelken Robert D 2002 Chromium based regulations and greening in metal finishing industries in the USA Environmental Science amp Policy 5 2 121 133 doi 10 1016 S1462 9011 02 00028 X Soderberg Tim 3 June 2019 Oxidizing Agents LibreTexts MindTouch Retrieved 8 September 2019 Roth Alexander 1994 Vacuum Sealing Techniques Springer Science amp Business Media pp 118 ISBN 978 1 56396 259 2 Lancashire Robert J 27 October 2008 Determination of iron using potassium dichromate Redox indicators The Department of Chemistry UWI Jamaica Retrieved 8 September 2019 Garverick Linda 1994 Corrosion in the Petrochemical Industry ASM International ISBN 978 0 87170 505 1 Shahid Ul Islam 18 July 2017 Plant Based Natural Products Derivatives and Applications Wiley pp 74 ISBN 978 1 119 42388 1 Vincent JB 2013 Chapter 6 Chromium Is It Essential Pharmacologically Relevant or Toxic In Astrid Sigel Helmut Sigel Roland KO Sigel eds Interrelations between Essential Metal Ions and Human Diseases Metal Ions in Life Sciences Vol 13 Springer pp 171 198 doi 10 1007 978 94 007 7500 8 6 ISBN 978 94 007 7499 5 PMID 24470092 Maret Wolfgang 2019 Chapter 9 Chromium Supplementation in Human Health Metabolic Syndrome and Diabetes In Sigel Astrid Freisinger Eva Sigel Roland K O Carver Peggy L eds Essential Metals in Medicine Therapeutic Use and Toxicity of Metal Ions in the Clinic Metal Ions in Life Sciences Vol 19 Berlin de Gruyter GmbH pp 231 251 doi 10 1515 9783110527872 015 ISBN 978 3 11 052691 2 PMID 30855110 European Food Safety Authority 2014 Scientific Opinion on Dietary Reference Values for chromium EFSA Journal 12 10 3845 doi 10 2903 j efsa 2014 3845 Di Bona KR Love S Rhodes NR McAdory D Sinha SH Kern N Kent J Strickland J Wilson A Beaird J Ramage J Rasco JF Vincent JB 2011 Chromium is not an essential trace element for mammals effects of a low chromium diet J Biol Inorg Chem 16 3 381 390 doi 10 1007 s00775 010 0734 y PMID 21086001 S2CID 22376660 Wise SS Wise JP Sr 2012 Chromium and genomic stability Mutation Research Fundamental and Molecular Mechanisms of Mutagenesis 733 1 2 78 82 doi 10 1016 j mrfmmm 2011 12 002 PMC 4138963 PMID 22192535 ToxFAQs Chromium Agency for Toxic Substances amp Disease Registry Centers for Disease Control and Prevention February 2001 Archived from the original on 8 July 2014 Retrieved 2 October 2007 Vincent JB 2015 Is the Pharmacological Mode of Action of Chromium III as a Second Messenger Biological Trace Element Research 166 1 7 12 doi 10 1007 s12011 015 0231 9 PMID 25595680 S2CID 16895342 a b Thor MY Harnack L King D Jasthi B Pettit J 2011 Evaluation of the comprehensiveness and reliability of the chromium composition of foods in the literature Journal of Food Composition and Analysis 24 8 1147 1152 doi 10 1016 j jfca 2011 04 006 PMC 3467697 PMID 23066174 Kamerud KL Hobbie KA Anderson KA 2013 Stainless steel leaches nickel and chromium into foods during cooking Journal of Agricultural and Food Chemistry 61 39 9495 9501 doi 10 1021 jf402400v PMC 4284091 PMID 23984718 Flint GN Packirisamy S 1997 Purity of food cooked in stainless steel utensils Food Additives and Contaminants 14 2 115 126 doi 10 1080 02652039709374506 PMID 9102344 a b Chromium Nutrient Reference Values for Australia and New Zealand 2014 Retrieved 4 October 2018 a b Nutrient Requirements and Recommended Dietary Allowances for Indians A Report of the Expert Group of the Indian Council of Medical Research pp 283 295 2009 PDF Archived from the original PDF on 15 June 2016 Retrieved 3 October 2018 a b DRIs for Chromium mg day PDF Overview of Dietary Reference Intakes for Japanese 2015 p 41 Retrieved 4 October 2018 a b c Chromium IN Dietary Reference Intakes for Vitamin A Vitamin K Arsenic Boron Chromium Chromium Iodine Iron Manganese Molybdenum Nickel Silicon Vanadium and Chromium Institute of Medicine U S Panel on Micronutrients National Academy Press 2001 pp 197 223 Retrieved 3 October 2018 a b Overview on Dietary Reference Values for the EU population as derived by the EFSA Panel on Dietetic Products Nutrition and Allergies PDF 2017 Tolerable Upper Intake Levels For Vitamins And Minerals PDF European Food Safety Authority 2006 Federal Register May 27 2016 Food Labeling Revision of the Nutrition and Supplement Facts Labels FR page 33982 PDF Daily Value Reference of the Dietary Supplement Label Database DSLD Dietary Supplement Label Database DSLD Archived from the original on 7 April 2020 Retrieved 16 May 2020 USDA Food Composition Databases United States Department of Agriculture Agricultural Research Service April 2018 Retrieved 4 October 2018 Kumpulainen JT 1992 Chromium content of foods and diets Biological Trace Element Research 32 1 3 9 18 doi 10 1007 BF02784582 PMID 1375091 S2CID 10189109 Grijalva Haro MI Ballesteros Vazquez MN Cabrera Pacheco RM 2001 Chromium content in foods and dietary intake estimation in the Northwest of Mexico Arch Latinoam Nutr in Spanish 51 1 105 110 PMID 11515227 a b Kantor Elizabeth D Rehm Colin D Du Mengmeng White Emily Giovannucci Edward L 11 October 2017 Trends in Dietary Supplement Use Among US Adults From 1999 2012 JAMA 316 14 1464 1474 doi 10 1001 jama 2016 14403 PMC 5540241 PMID 27727382 a b Stehle P Stoffel Wagner B Kuh KS 6 April 2014 Parenteral trace element provision recent clinical research and practical conclusions European Journal of Clinical Nutrition 70 8 886 893 doi 10 1038 ejcn 2016 53 PMC 5399133 PMID 27049031 Finch Carolyn Weiglein February 2015 Review of trace mineral requirements for preterm infants What are the current recommendations for clinical practice Nutrition in Clinical Practice 30 1 44 58 doi 10 1177 0884533614563353 PMID 25527182 a b Vincent John B 2010 Chromium Celebrating 50 years as an essential element Dalton Transactions 39 16 3787 3794 doi 10 1039 B920480F PMID 20372701 FDA Qualified Health Claims Letters of Enforcement Discretion Letters of Denial U S Food and Drug Administration Docket 2004Q 0144 August 2005 Monograph Chromium from Chromium picolinate Health Canada 9 December 2009 Retrieved 18 October 2018 a b Scientific Opinion on the substantiation of health claims related to chromium and contribution to normal macronutrient metabolism ID 260 401 4665 4666 4667 maintenance of normal blood glucose concentrations ID 262 4667 contribution to the maintenance or achievement of a normal body weight ID 339 4665 4666 and reduction of tiredness and fatigue ID 261 pursuant to Article 13 1 of Regulation EC No 1924 2006 Archived 21 April 2020 at the Wayback Machine European Food Safety Authority EFSA J 2010 8 10 1732 San Mauro Martin I Ruiz Leon AM Camina Martin MA Garicano Vilar E Collado Yurrita L Mateo Silleras B Redondo P 2016 Chromium supplementation in patients with type 2 diabetes and high risk of type 2 diabetes a meta analysis of randomized controlled trials Nutr Hosp in Spanish 33 1 27 doi 10 20960 nh 27 PMID 27019254 Abdollahi M Farshchi A Nikfar S Seyedifar M 2013 Effect of chromium on glucose and lipid profiles in patients with type 2 diabetes a meta analysis review of randomized trials J Pharm Pharm Sci 16 1 99 114 doi 10 18433 J3G022 PMID 23683609 Suksomboon N Poolsup N Yuwanakorn A 17 March 2013 Systematic review and meta analysis of the efficacy and safety of chromium supplementation in diabetes J Clin Pharm Ther 39 3 292 306 doi 10 1111 jcpt 12147 PMID 24635480 S2CID 22326435 Bailey Christopher H January 2014 Improved meta analytic methods show no effect of chromium supplements on fasting glucose Biol Trace Elem Res 157 1 1 8 doi 10 1007 s12011 013 9863 9 PMID 24293356 S2CID 2441511 Costello Rebecca B Dwyer Johanna T Bailey Regan L 30 May 2016 Chromium supplements for glycemic control in type 2 diabetes limited evidence of effectiveness Nutrition Reviews 74 7 455 468 doi 10 1093 nutrit nuw011 PMC 5009459 PMID 27261273 a b Tian Honglian Guo Xiaohu Wang Xiyu He Zhiyun Sun Rao Ge Sai Zhang Zongjiu 2013 Chromium picolinate supplementation for overweight or obese adults Cochrane Database Syst Rev 2013 11 CD010063 doi 10 1002 14651858 CD010063 pub2 PMC 7433292 PMID 24293292 a b Onakpoya I Posadzki P Ernst E 2013 Chromium supplementation in overweight and obesity a systematic review and meta analysis of randomized clinical trials Obes Rev 14 6 496 507 doi 10 1111 obr 12026 PMID 23495911 S2CID 21832321 Lefavi RG Anderson RA Keith RE Wilson GD McMillan JL Stone MH 1992 Efficacy of chromium supplementation in athletes emphasis on anabolism International Journal of Sport Nutrition 2 2 111 122 doi 10 1123 ijsn 2 2 111 PMID 1299487 Vincent JB 2003 The potential value and toxicity of chromium picolinate as a nutritional supplement weight loss agent and muscle development agent Sports Med 33 3 213 230 doi 10 2165 00007256 200333030 00004 PMID 12656641 S2CID 9981172 Jenkinson DM Harbert AJ 2008 Supplements and sports Am Fam Physician 78 9 1039 1046 PMID 19007050 Maughan RJ Burke LM et al 2018 IOC Consensus Statement Dietary Supplements and the High Performance Athlete International Journal of Sport Nutrition and Exercise Metabolism 28 2 104 125 doi 10 1123 ijsnem 2018 0020 PMC 5867441 PMID 29589768 Islam MM Karim MR Zheng X Li X 2018 Heavy Metal and Metalloid Pollution of Soil Water and Foods in Bangladesh A Critical Review International Journal of Environmental Research and Public Health 15 12 2825 doi 10 3390 ijerph15122825 PMC 6313774 PMID 30544988 a b Bakshi A Panigrahi AK 2018 A comprehensive review on chromium induced alterations in fresh water fishes Toxicol Rep 5 440 447 doi 10 1016 j toxrep 2018 03 007 PMC 5977408 PMID 29854615 Ahmed AR Jha AN Davies SJ 2012 The efficacy of chromium as a growth enhancer for mirror carp Cyprinus carpio L an integrated study using biochemical genetic and histological responses Biol Trace Elem Res 148 2 187 197 doi 10 1007 s12011 012 9354 4 PMID 22351105 S2CID 16154712 Barceloux Donald G Barceloux Donald 1999 Chromium Clinical Toxicology 37 2 173 194 doi 10 1081 CLT 100102418 PMID 10382554 a b Katz SA Salem H 1992 The toxicology of chromium with respect to its chemical speciation A review Journal of Applied Toxicology 13 3 217 224 doi 10 1002 jat 2550130314 PMID 8326093 S2CID 31117557 Eastmond DA MacGregor JT Slesinski RS 2008 Trivalent Chromium Assessing the Genotoxic Risk of an Essential Trace Element and Widely Used Human and Animal Nutritional Supplement Critical Reviews in Toxicology 38 3 173 190 doi 10 1080 10408440701845401 PMID 18324515 S2CID 21033504 NIOSH Pocket Guide to Chemical Hazards 0141 National Institute for Occupational Safety and Health NIOSH Dayan AD Paine AJ 2001 Mechanisms of chromium toxicity carcinogenicity and allergenicity Review of the literature from 1985 to 2000 Human amp Experimental Toxicology 20 9 439 451 doi 10 1191 096032701682693062 PMID 11776406 S2CID 31351037 Newman D 1890 A case of adeno carcinoma of the left inferior turbinated body and perforation of the nasal septum in the person of a worker in chrome pigments Glasgow Medical Journal 33 469 470 Langard S 1990 One Hundred Years of Chromium and Cancer A Review of Epidemiological Evidence and Selected Case Reports American Journal of Industrial Medicine 17 2 189 214 doi 10 1002 ajim 4700170205 PMID 2405656 Cohen MD Kargacin B Klein CB Costa M 1993 Mechanisms of chromium carcinogenicity and toxicity Critical Reviews in Toxicology 23 3 255 281 doi 10 3109 10408449309105012 PMID 8260068 Methods to Develop Inhalation Cancer Risk Estimates for Chromium and Nickel Compounds Research Triangle Park NC U S Environmental Protection Agency Office of Air Quality Planning and Standards Health and Environmental Impacts Division 2011 Retrieved 19 March 2015 Ngan V 2002 Chrome Allergy DermNet NZ Basketter David Horev L Slodovnik D Merimes S Trattner A Ingber A 2000 Investigation of the threshold for allergic reactivity to chromium Contact Dermatitis 44 2 70 74 doi 10 1034 j 1600 0536 2001 440202 x PMID 11205406 S2CID 45426346 Baselt Randall C 2008 Disposition of Toxic Drugs and Chemicals in Man 8th ed Foster City Biomedical Publications pp 305 307 ISBN 978 0 9626523 7 0 US water has large amounts of likely carcinogen study Yahoo News 19 December 2010 Archived from the original on 23 December 2010 Retrieved 19 December 2010 James Bruce 1996 The challenge of remediating chromium contaminated soil Environmental Science and Technology 30 6 248A 251A doi 10 1021 es962269h PMID 21648723 General bibliography EditGreenwood Norman N Earnshaw Alan 1997 Chemistry of the Elements 2nd ed Butterworth Heinemann ISBN 978 0 08 037941 8 External links Edit Wikimedia Commons has media related to Chromium Look up chromium in Wiktionary the free dictionary ATSDR Case Studies in Environmental Medicine Chromium Toxicity U S Department of Health and Human Services IARC Monograph Chromium and Chromium compounds It s Elemental The Element Chromium The Merck Manual Mineral Deficiency and Toxicity National Institute for Occupational Safety and Health Chromium Page Chromium at The Periodic Table of Videos University of Nottingham Chromium Encyclopaedia Britannica Vol 6 11th ed 1911 pp 296 298 Retrieved from https en wikipedia org w index php title Chromium amp oldid 1136446405, wikipedia, wiki, book, books, library,

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