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Iron oxide

February 16, 2024

Iron oxides are chemical compounds composed of iron and oxygen. Several iron oxides are recognized. Often they are non-stoichiometric. Oxyhydroxides are a related class of compounds, perhaps the best known of which is rust.[1]

Electrochemically oxidized iron (rust)

Iron oxides and oxyhydroxides are widespread in nature and play an important role in many geological and biological processes. They are used as iron ores, pigments, catalysts, and in thermite, and occur in hemoglobin. Iron oxides are inexpensive and durable pigments in paints, coatings and colored concretes. Colors commonly available are in the "earthy" end of the yellow/orange/red/brown/black range. When used as a food coloring, it has E number E172.

Stoichiometries edit

 
Iron oxide pigment. The brown color indicates that iron is at the oxidation state +3.
 
Green and reddish brown stains on a limestone core sample, respectively corresponding to oxides/hydroxides of Fe2+ and Fe3+.

Iron oxides feature as ferrous (Fe(II)) or ferric (Fe(III)) or both. They adopt octahedral or tetrahedral coordination geometry. Only a few oxides are significant at the earth's surface, particularly wüstite, magnetite, and hematite.

Thermal expansion edit

Iron oxide CTE (× 10−6 °C−1)
Fe2O3 14.9[6]
Fe3O4 >9.2[6]
FeO 12.1[6]

Oxide-hydroxides edit

Main article: iron(III) oxide-hydroxide
  • goethite (α-FeOOH),
  • akaganéite (β-FeOOH),
  • lepidocrocite (γ-FeOOH),
  • feroxyhyte (δ-FeOOH),
  • ferrihydrite (Fe5HO8 · 4 H2O approx., or 5 Fe2O3 · 9 H2O, better recast as FeOOH · 0.4 H2O)
  • high-pressure pyrite-structured FeOOH.[7] Once dehydration is triggered, this phase may form FeO2Hx (0 < x < 1).[8]
  • green rust (FeIII
    x    FeII
    y    OH3x + y − z (A−)z where A− is Cl− or 0.5 SO2−4)

Reactions edit

In blast furnaces and related factories, iron oxides are converted to the metal. Typical reducing agents are various forms of carbon. A representative reaction starts with ferric oxide:[9]

2 Fe2O3 + 3 C → 4 Fe + 3 CO2

In nature edit

Iron is stored in many organisms in the form of ferritin, which is a ferrous oxide encased in a solubilizing protein sheath.[10]

Species of bacteria, including Shewanella oneidensis, Geobacter sulfurreducens and Geobacter metallireducens, use iron oxides as terminal electron acceptors.[11]

Uses edit

Almost all iron ores are oxides, so in that sense these materials are important precursors to iron metal and its many alloys.

Iron oxides are important pigments, coming in a variety of colors (black, red, yellow). Among their many advantages, they are inexpensive, strongly colored, and nontoxic.[12]

Magnetite is a component of magnetic recording tapes.

See also edit

References edit

  1. ^ Cornell., RM.; Schwertmann, U (2003). The iron oxides: structure, properties, reactions, occurrences and. Wiley VCH. ISBN 978-3-527-30274-1.
  2. ^ Lavina, B.; Dera, P.; Kim, E.; Meng, Y.; Downs, R. T.; Weck, P. F.; Sutton, S. R.; Zhao, Y. (Oct 2011). "Discovery of the recoverable high-pressure iron oxide Fe4O5". Proceedings of the National Academy of Sciences. 108 (42): 17281–17285. Bibcode:2011PNAS..10817281L. doi:10.1073/pnas.1107573108. PMC 3198347. PMID 21969537.
  3. ^ Lavina, Barbara; Meng, Yue (2015). "Synthesis of Fe5O6". Science Advances. 1 (5): e1400260. doi:10.1126/sciadv.1400260. PMC 4640612. PMID 26601196.
  4. ^ a b Bykova, E.; Dubrovinsky, L.; Dubrovinskaia, N.; Bykov, M.; McCammon, C.; Ovsyannikov, S. V.; Liermann, H. -P.; Kupenko, I.; Chumakov, A. I.; Rüffer, R.; Hanfland, M.; Prakapenka, V. (2016). "Structural complexity of simple Fe2O3 at high pressures and temperatures". Nature Communications. 7: 10661. Bibcode:2016NatCo...710661B. doi:10.1038/ncomms10661. PMC 4753252. PMID 26864300.
  5. ^ Merlini, Marco; Hanfland, Michael; Salamat, Ashkan; Petitgirard, Sylvain; Müller, Harald (2015). "The crystal structures of Mg2Fe2C4O13, with tetrahedrally coordinated carbon, and Fe13O19, synthesized at deep mantle conditions". American Mineralogist. 100 (8–9): 2001–2004. Bibcode:2015AmMin.100.2001M. doi:10.2138/am-2015-5369. S2CID 54496448.
  6. ^ a b c Fakouri Hasanabadi, M.; Kokabi, A.H.; Nemati, A.; Zinatlou Ajabshir, S. (February 2017). "Interactions near the triple-phase boundaries metal/glass/air in planar solid oxide fuel cells". International Journal of Hydrogen Energy. 42 (8): 5306–5314. doi:10.1016/j.ijhydene.2017.01.065. ISSN 0360-3199.
  7. ^ Nishi, Masayuki; Kuwayama, Yasuhiro; Tsuchiya, Jun; Tsuchiya, Taku (2017). "The pyrite-type high-pressure form of FeOOH". Nature. 547 (7662): 205–208. Bibcode:2017Natur.547..205N. doi:10.1038/nature22823. ISSN 1476-4687. PMID 28678774. S2CID 205257075.
  8. ^ Hu, Qingyang; Kim, Duckyoung; Liu, Jin; Meng, Yue; Liuxiang, Yang; Zhang, Dongzhou; Mao, Wendy L.; Mao, Ho-kwang (2017). "Dehydrogenation of goethite in Earth's deep lower mantle". Proceedings of the National Academy of Sciences. 114 (7): 1498–1501. Bibcode:2017PNAS..114.1498H. doi:10.1073/pnas.1620644114. PMC 5320987. PMID 28143928.
  9. ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 1072. ISBN 978-0-08-037941-8.
  10. ^ Honarmand Ebrahimi, Kourosh; Hagedoorn, Peter-Leon; Hagen, Wilfred R. (2015). "Unity in the Biochemistry of the Iron-Storage Proteins Ferritin and Bacterioferritin". Chemical Reviews. 115 (1): 295–326. doi:10.1021/cr5004908. PMID 25418839.
  11. ^ Bretschger, O.; Obraztsova, A.; Sturm, C. A.; Chang, I. S.; Gorby, Y. A.; Reed, S. B.; Culley, D. E.; Reardon, C. L.; Barua, S.; Romine, M. F.; Zhou, J.; Beliaev, A. S.; Bouhenni, R.; Saffarini, D.; Mansfeld, F.; Kim, B.-H.; Fredrickson, J. K.; Nealson, K. H. (20 July 2007). "Current Production and Metal Oxide Reduction by Shewanella oneidensis MR-1 Wild Type and Mutants". Applied and Environmental Microbiology. 73 (21): 7003–7012. Bibcode:2007ApEnM..73.7003B. doi:10.1128/AEM.01087-07. PMC 2223255. PMID 17644630.
  12. ^ Buxbaum, Gunter; Printzen, Helmut; Mansmann, Manfred; Räde, Dieter; Trenczek, Gerhard; Wilhelm, Volker; Schwarz, Stefanie; Wienand, Henning; Adel (2009). "Pigments, Inorganic, 3. Colored Pigments". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.n20_n02. ISBN 978-3527306732.

External links edit

 
Wikimedia Commons has media related to Iron oxides.
  • The Iron One-Pot Reaction
  • Iron Oxide Pigments Statistics and Information
  • CDC – NIOSH Pocket Guide to Chemical Hazards

February 16, 2024
iron, oxide, chemical, compounds, composed, iron, oxygen, several, iron, oxides, recognized, often, they, stoichiometric, oxyhydroxides, related, class, compounds, perhaps, best, known, which, rust, electrochemically, oxidized, iron, rust, oxyhydroxides, wides. Iron oxides are chemical compounds composed of iron and oxygen Several iron oxides are recognized Often they are non stoichiometric Oxyhydroxides are a related class of compounds perhaps the best known of which is rust 1 Electrochemically oxidized iron rust Iron oxides and oxyhydroxides are widespread in nature and play an important role in many geological and biological processes They are used as iron ores pigments catalysts and in thermite and occur in hemoglobin Iron oxides are inexpensive and durable pigments in paints coatings and colored concretes Colors commonly available are in the earthy end of the yellow orange red brown black range When used as a food coloring it has E number E172 Contents 1 Stoichiometries 2 Thermal expansion 3 Oxide hydroxides 4 Reactions 4 1 In nature 5 Uses 6 See also 7 References 8 External linksStoichiometries edit nbsp Iron oxide pigment The brown color indicates that iron is at the oxidation state 3 nbsp Green and reddish brown stains on a limestone core sample respectively corresponding to oxides hydroxides of Fe2 and Fe3 Iron oxides feature as ferrous Fe II or ferric Fe III or both They adopt octahedral or tetrahedral coordination geometry Only a few oxides are significant at the earth s surface particularly wustite magnetite and hematite Oxides of FeIIFeO iron II oxide wustite Mixed oxides of FeII and FeIIIFe3O4 Iron II III oxide magnetite Fe4O5 2 Fe5O6 3 Fe5O7 4 Fe25O32 4 Fe13O19 5 Oxides of FeIIIFe2O3 iron III oxide a Fe2O3 alpha phase hematite b Fe2O3 beta phase g Fe2O3 gamma phase maghemite e Fe2O3 epsilon phaseThermal expansion editIron oxide CTE 10 6 C 1 Fe2O3 14 9 6 Fe3O4 gt 9 2 6 FeO 12 1 6 Oxide hydroxides editMain article iron III oxide hydroxide goethite a FeOOH akaganeite b FeOOH lepidocrocite g FeOOH feroxyhyte d FeOOH ferrihydrite Fe5HO8 4 H2O approx or 5 Fe2O3 9 H2O better recast as FeOOH 0 4 H2O high pressure pyrite structured FeOOH 7 Once dehydration is triggered this phase may form FeO2Hx 0 lt x lt 1 8 green rust FeIIIx FeIIy OH3x y z A z where A is Cl or 0 5 SO2 4 Reactions editIn blast furnaces and related factories iron oxides are converted to the metal Typical reducing agents are various forms of carbon A representative reaction starts with ferric oxide 9 2 Fe2O3 3 C 4 Fe 3 CO2In nature edit Iron is stored in many organisms in the form of ferritin which is a ferrous oxide encased in a solubilizing protein sheath 10 Species of bacteria including Shewanella oneidensis Geobacter sulfurreducens and Geobacter metallireducens use iron oxides as terminal electron acceptors 11 Uses editAlmost all iron ores are oxides so in that sense these materials are important precursors to iron metal and its many alloys Iron oxides are important pigments coming in a variety of colors black red yellow Among their many advantages they are inexpensive strongly colored and nontoxic 12 Magnetite is a component of magnetic recording tapes See also editGreat Oxidation Event Iron cycle Iron oxide nanoparticle Limonite List of inorganic pigmentsReferences edit Cornell RM Schwertmann U 2003 The iron oxides structure properties reactions occurrences and Wiley VCH ISBN 978 3 527 30274 1 Lavina B Dera P Kim E Meng Y Downs R T Weck P F Sutton S R Zhao Y Oct 2011 Discovery of the recoverable high pressure iron oxide Fe4O5 Proceedings of the National Academy of Sciences 108 42 17281 17285 Bibcode 2011PNAS 10817281L doi 10 1073 pnas 1107573108 PMC 3198347 PMID 21969537 Lavina Barbara Meng Yue 2015 Synthesis of Fe5O6 Science Advances 1 5 e1400260 doi 10 1126 sciadv 1400260 PMC 4640612 PMID 26601196 a b Bykova E Dubrovinsky L Dubrovinskaia N Bykov M McCammon C Ovsyannikov S V Liermann H P Kupenko I Chumakov A I Ruffer R Hanfland M Prakapenka V 2016 Structural complexity of simple Fe2O3 at high pressures and temperatures Nature Communications 7 10661 Bibcode 2016NatCo 710661B doi 10 1038 ncomms10661 PMC 4753252 PMID 26864300 Merlini Marco Hanfland Michael Salamat Ashkan Petitgirard Sylvain Muller Harald 2015 The crystal structures of Mg2Fe2C4O13 with tetrahedrally coordinated carbon and Fe13O19 synthesized at deep mantle conditions American Mineralogist 100 8 9 2001 2004 Bibcode 2015AmMin 100 2001M doi 10 2138 am 2015 5369 S2CID 54496448 a b c Fakouri Hasanabadi M Kokabi A H Nemati A Zinatlou Ajabshir S February 2017 Interactions near the triple phase boundaries metal glass air in planar solid oxide fuel cells International Journal of Hydrogen Energy 42 8 5306 5314 doi 10 1016 j ijhydene 2017 01 065 ISSN 0360 3199 Nishi Masayuki Kuwayama Yasuhiro Tsuchiya Jun Tsuchiya Taku 2017 The pyrite type high pressure form of FeOOH Nature 547 7662 205 208 Bibcode 2017Natur 547 205N doi 10 1038 nature22823 ISSN 1476 4687 PMID 28678774 S2CID 205257075 Hu Qingyang Kim Duckyoung Liu Jin Meng Yue Liuxiang Yang Zhang Dongzhou Mao Wendy L Mao Ho kwang 2017 Dehydrogenation of goethite in Earth s deep lower mantle Proceedings of the National Academy of Sciences 114 7 1498 1501 Bibcode 2017PNAS 114 1498H doi 10 1073 pnas 1620644114 PMC 5320987 PMID 28143928 Greenwood Norman N Earnshaw Alan 1997 Chemistry of the Elements 2nd ed Butterworth Heinemann p 1072 ISBN 978 0 08 037941 8 Honarmand Ebrahimi Kourosh Hagedoorn Peter Leon Hagen Wilfred R 2015 Unity in the Biochemistry of the Iron Storage Proteins Ferritin and Bacterioferritin Chemical Reviews 115 1 295 326 doi 10 1021 cr5004908 PMID 25418839 Bretschger O Obraztsova A Sturm C A Chang I S Gorby Y A Reed S B Culley D E Reardon C L Barua S Romine M F Zhou J Beliaev A S Bouhenni R Saffarini D Mansfeld F Kim B H Fredrickson J K Nealson K H 20 July 2007 Current Production and Metal Oxide Reduction by Shewanella oneidensis MR 1 Wild Type and Mutants Applied and Environmental Microbiology 73 21 7003 7012 Bibcode 2007ApEnM 73 7003B doi 10 1128 AEM 01087 07 PMC 2223255 PMID 17644630 Buxbaum Gunter Printzen Helmut Mansmann Manfred Rade Dieter Trenczek Gerhard Wilhelm Volker Schwarz Stefanie Wienand Henning Adel 2009 Pigments Inorganic 3 Colored Pigments Ullmann s Encyclopedia of Industrial Chemistry Weinheim Wiley VCH doi 10 1002 14356007 n20 n02 ISBN 978 3527306732 External links edit nbsp Wikimedia Commons has media related to Iron oxides Information from Nano Oxides Inc on Fe2O3 The Iron One Pot Reaction Iron Oxide Pigments Statistics and Information CDC NIOSH Pocket Guide to Chemical Hazards Retrieved from https en wikipedia org w index php title Iron oxide amp oldid 1205666663, wikipedia, wiki, book, books, library,

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