Magnesium carbonate, MgCO3 (archaic name magnesia alba), is an inorganic salt that is a colourless or white solid. Several hydrated and basic forms of magnesium carbonate also exist as minerals.
This article may be expanded with text translated from the corresponding article in German. (December 2018) Click [show] for important translation instructions.
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The most common magnesium carbonate forms are the anhydrous salt called magnesite (MgCO3), and the di, tri, and pentahydrates known as barringtonite (MgCO3·2H2O), nesquehonite (MgCO3·3H2O), and lansfordite (MgCO3·5H2O), respectively.[6] Some basic forms such as artinite (Mg2CO3(OH)2·3H2O), hydromagnesite (Mg5(CO3)4(OH)2·4H2O), and dypingite (Mg5(CO3)4(OH)2·5H2O) also occur as minerals. All of those minerals are colouress or white.
The dihydrate has a triclinic structure, while the trihydrate has a monoclinic structure.
References to "light" and "heavy" magnesium carbonates actually refer to the magnesium hydroxy carbonates hydromagnesite and dypingite, respectively.[7]
Preparation
Magnesium carbonate is ordinarily obtained by mining the mineral magnesite. Seventy percent of the world's supply is mined and prepared in China.[8]
Magnesium carbonate can be prepared in laboratory by reaction between any soluble magnesium salt and sodium bicarbonate:
If magnesium chloride (or sulfate) is treated with aqueous sodium carbonate, a precipitate of basic magnesium carbonate – a hydrated complex of magnesium carbonate and magnesium hydroxide – rather than magnesium carbonate itself is formed:
High purity industrial routes include a path through magnesium bicarbonate, which can be formed by combining a slurry of magnesium hydroxide and carbon dioxide at high pressure and moderate temperature.[6] The bicarbonate is then vacuum dried, causing it to lose carbon dioxide and a molecule of water:
Mg(OH)2 + 2 CO2 → Mg(HCO3)2
Mg(HCO3)2 → MgCO3 + CO2 + H2O
Chemical properties
With acids
Like many common group 2 metal carbonates, magnesium carbonate reacts with aqueous acids to release carbon dioxide and water:
MgCO3 + 2 HCl → MgCl2 + CO2 + H2O
MgCO3 + H2SO4 → MgSO4 + CO2 + H2O
Decomposition
At high temperatures MgCO3 decomposes to magnesium oxide and carbon dioxide. This process is important in the production of magnesium oxide.[6] This process is called calcining:
MgCO3 → MgO + CO2 (ΔH = +118 kJ/mol)
The decomposition temperature is given as 350 °C (662 °F).[9][10] However, calcination to the oxide is generally not considered complete below 900 °C due to interfering readsorption of liberated carbon dioxide.
The hydrates of the salts lose water at different temperatures during decomposition.[11] For example, in the trihydrate MgCO3·3H2O, which molecular formula may be written as Mg(HCO3)(OH)·2H2O, the dehydration steps occur at 157 °C and 179 °C as follows:[11]
Mg(HCO3)(OH)·2(H2O) → Mg(HCO3)(OH)·(H2O) + H2O at 157 °C
Climber Jan Hojer blows surplus chalk from his hand. Boulder World Cup 2015
Because of its low solubility in water and hygroscopic properties, MgCO3 was first added to salt in 1911 to make it flow more freely. The Morton Salt company adopted the slogan "When it rains it pours", meaning that its salt containing MgCO3 would not stick together in humid weather.[12] Magnesium carbonate, most often referred to as "chalk", is also used as a drying agent on athletes' hands in rock climbing, gymnastics, weightlifting and other sports in which a firm grip is necessary.[8]
As a food additive, magnesium carbonate is known as E504. Its only known side effect is that it may work as a laxative in high concentrations.[13]
Magnesium carbonate is used in taxidermy for whitening skulls. It can be mixed with hydrogen peroxide to create a paste, which is spread on the skull to give it a white finish.
In addition, high purity magnesium carbonate is used as an antacid and as an additive in table salt to keep it free flowing. Magnesium carbonate can do this because it does not dissolve in water, only in acid, where it will effervesce (bubble).[15]
Safety
Magnesium carbonate is non-toxic and non-flammable.
^Bénézeth, Pascale; Saldi, Giuseppe D.; Dandurand, Jean-Louis; Schott, Jacques (2011). "Experimental determination of the solubility product of magnesite at 50 to 200 °C". Chemical Geology. 286 (1–2): 21–31. Bibcode:2011ChGeo.286...21B. doi:10.1016/j.chemgeo.2011.04.016.
^ abRoss, Nancy L. (1997). "The equation of state and high-pressure behavior of magnesite". Am. Mineral.82 (7–8): 682–688. doi:10.2138/am-1997-7-805.
^ abZumdahl, Steven S. (2009). Chemical Principles 6th Ed. Houghton Mifflin Company. p. A22. ISBN978-0-618-94690-7.
^ abcdMargarete Seeger; Walter Otto; Wilhelm Flick; Friedrich Bickelhaupt; Otto S. Akkerman. "Magnesium Compounds". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a15_595.pub2.
^Botha, A.; Strydom, C.A. (2001). "Preparation of a magnesium hydroxy carbonate from magnesium hydroxide". Hydrometallurgy. 62 (3): 175. doi:10.1016/S0304-386X(01)00197-9.
^ abAllf, Bradley (21 May 2018). "The Hidden Environmental Cost of Climbing Chalk". Climbing Magazine. Cruz Bay Publishing. Retrieved 22 May 2018. In fact, China produces 70 percent of the world's magnesite. Most of that production—both mining and processing—is concentrated in a small corner of Liaoning, a hilly industrial province in northeast China between Beijing and North Korea.
^Noronha, Shonan (2015). Certified Technology Specialist-Installation. McGraw Hill Education. p. 256. ISBN978-0071835657.
^"What Is Magnesium Carbonate?". Sciencing. Retrieved 15 April 2018.
^British Pharmacopoeia Commission Secretariat (2009). (PDF). Archived from the original (PDF) on 11 April 2009. Retrieved 31 January 2010.
^(PDF). 2006. Archived from the original (PDF) on 22 July 2011. Retrieved 31 January 2010.
External links
Wikimedia Commons has media related to Magnesium carbonate.
International Chemical Safety Card 0969
NIST Standard Reference Database
January 20, 2023
magnesium, carbonate, mgco3, archaic, name, magnesia, alba, inorganic, salt, that, colourless, white, solid, several, hydrated, basic, forms, magnesium, carbonate, also, exist, minerals, namesother, names, magnesitebarringtonite, dihydrate, nesequehonite, trih. Magnesium carbonate MgCO3 archaic name magnesia alba is an inorganic salt that is a colourless or white solid Several hydrated and basic forms of magnesium carbonate also exist as minerals Magnesium carbonate NamesOther names MagnesiteBarringtonite dihydrate Nesequehonite trihydrate Lansfordite pentahydrate IdentifiersCAS Number 546 93 0 anhydrous Y17968 26 2 monohydrate Y5145 48 2 dihydrate N14457 83 1 trihydrate N61042 72 6 pentahydrate N3D model JSmol Interactive imageChEBI CHEBI 31793 YChEMBL ChEMBL1200736 NChemSpider 10563 YECHA InfoCard 100 008 106E number E504 i acidity regulators PubChem CID 11029RTECS number OM2470000UNII 0IHC698356 Y0E53J927NA monohydrate YCompTox Dashboard EPA DTXSID4049660InChI InChI 1S CH2O3 Mg c2 1 3 4 h H2 2 3 4 q 2 p 2 YKey ZLNQQNXFFQJAID UHFFFAOYSA L YInChI 1 CH2O3 Mg c2 1 3 4 h H2 2 3 4 q 2 p 2Key ZLNQQNXFFQJAID NUQVWONBAUSMILES Mg 2 O C O OPropertiesChemical formula MgCO3Molar mass 84 3139 g mol anhydrous Appearance Colourless crystals or white solid HygroscopicOdor OdorlessDensity 2 958 g cm3 anhydrous 2 825 g cm3 dihydrate 1 837 g cm3 trihydrate 1 73 g cm3 pentahydrate Melting point 350 C 662 F 623 K decomposes anhydrous 165 C 329 F 438 K trihydrate Solubility in water Anhydrous 0 0139 g 100 ml 25 C 0 0063 g 100 ml 100 C 1 Solubility product Ksp 10 7 8 2 Solubility Soluble in acid aqueous CO2 Insoluble in acetone ammoniaMagnetic susceptibility x 32 4 10 6 cm3 molRefractive index nD 1 717 anhydrous 1 458 dihydrate 1 412 trihydrate StructureCrystal structure TrigonalSpace group R3 c No 167 3 ThermochemistryHeat capacity C 75 6 J mol K 1 Std molarentropy S 298 65 7 J mol K 1 4 Std enthalpy offormation DfH 298 1113 kJ mol 4 Gibbs free energy DfG 1029 3 kJ mol 1 PharmacologyATC code A02AA01 WHO A06AD01 WHO HazardsNFPA 704 fire diamond 100Flash point Non flammableNIOSH US health exposure limits PEL Permissible TWA 15 mg m3 total TWA 5 mg m3 resp 5 Safety data sheet SDS ICSC 0969Related compoundsOther anions Magnesium bicarbonateOther cations Beryllium carbonateCalcium carbonateStrontium carbonateBarium carbonateRadium carbonateRelated compounds ArtiniteHydromagnesiteDypingiteExcept where otherwise noted data are given for materials in their standard state at 25 C 77 F 100 kPa N verify what is Y N Infobox references This article may be expanded with text translated from the corresponding article in German December 2018 Click show for important translation instructions Machine translation like DeepL or Google Translate is a useful starting point for translations but translators must revise errors as necessary and confirm that the translation is accurate rather than simply copy pasting machine translated text into the English Wikipedia Do not translate text that appears unreliable or low quality If possible verify the text with references provided in the foreign language article You must provide copyright attribution in the edit summary accompanying your translation by providing an interlanguage link to the source of your translation A model attribution edit summary is Content in this edit is translated from the existing German Wikipedia article at de Magnesiumcarbonat see its history for attribution You should also add the template Translated de Magnesiumcarbonat to the talk page For more guidance see Wikipedia Translation Contents 1 Forms 2 Preparation 3 Chemical properties 3 1 With acids 3 2 Decomposition 4 Uses 4 1 Medical use 5 Safety 6 Compendial status 7 See also 8 Notes and references 9 External linksForms EditThe most common magnesium carbonate forms are the anhydrous salt called magnesite MgCO3 and the di tri and pentahydrates known as barringtonite MgCO3 2H2O nesquehonite MgCO3 3H2O and lansfordite MgCO3 5H2O respectively 6 Some basic forms such as artinite Mg2CO3 OH 2 3H2O hydromagnesite Mg5 CO3 4 OH 2 4H2O and dypingite Mg5 CO3 4 OH 2 5H2O also occur as minerals All of those minerals are colouress or white Magnesite consists of colourless or white trigonal crystals The anhydrous salt is practically insoluble in water acetone and ammonia All forms of magnesium carbonate react with acids Magnesite crystallizes in the calcite structure wherein Mg2 is surrounded by six oxygen atoms 3 Crystal structure of magnesium carbonate Carbonate coordination Magnesium coordination Unit cell The dihydrate has a triclinic structure while the trihydrate has a monoclinic structure References to light and heavy magnesium carbonates actually refer to the magnesium hydroxy carbonates hydromagnesite and dypingite respectively 7 Preparation EditMagnesium carbonate is ordinarily obtained by mining the mineral magnesite Seventy percent of the world s supply is mined and prepared in China 8 Magnesium carbonate can be prepared in laboratory by reaction between any soluble magnesium salt and sodium bicarbonate MgCl2 aq 2 NaHCO3 aq MgCO3 s 2 NaCl aq H2O l CO2 g If magnesium chloride or sulfate is treated with aqueous sodium carbonate a precipitate of basic magnesium carbonate a hydrated complex of magnesium carbonate and magnesium hydroxide rather than magnesium carbonate itself is formed 5 MgCl2 aq 5 Na2CO3 aq 5 H2O l Mg4 CO3 3 OH 2 3H2O s Mg HCO3 2 aq 10 NaCl aq High purity industrial routes include a path through magnesium bicarbonate which can be formed by combining a slurry of magnesium hydroxide and carbon dioxide at high pressure and moderate temperature 6 The bicarbonate is then vacuum dried causing it to lose carbon dioxide and a molecule of water Mg OH 2 2 CO2 Mg HCO3 2 Mg HCO3 2 MgCO3 CO2 H2OChemical properties EditWith acids Edit Like many common group 2 metal carbonates magnesium carbonate reacts with aqueous acids to release carbon dioxide and water MgCO3 2 HCl MgCl2 CO2 H2O MgCO3 H2SO4 MgSO4 CO2 H2ODecomposition Edit At high temperatures MgCO3 decomposes to magnesium oxide and carbon dioxide This process is important in the production of magnesium oxide 6 This process is called calcining MgCO3 MgO CO2 DH 118 kJ mol The decomposition temperature is given as 350 C 662 F 9 10 However calcination to the oxide is generally not considered complete below 900 C due to interfering readsorption of liberated carbon dioxide The hydrates of the salts lose water at different temperatures during decomposition 11 For example in the trihydrate MgCO3 3H2O which molecular formula may be written as Mg HCO3 OH 2H2O the dehydration steps occur at 157 C and 179 C as follows 11 Mg HCO3 OH 2 H2O Mg HCO3 OH H2O H2O at 157 C Mg HCO3 OH H2O Mg HCO3 OH H2O at 179 CUses EditThe primary use of magnesium carbonate is the production of magnesium oxide by calcining Magnesite and dolomite minerals are used to produce refractory bricks 6 MgCO3 is also used in flooring fireproofing fire extinguishing compositions cosmetics dusting powder and toothpaste Other applications are as filler material smoke suppressant in plastics a reinforcing agent in neoprene rubber a drying agent and colour retention in foods Climber Jan Hojer blows surplus chalk from his hand Boulder World Cup 2015 Because of its low solubility in water and hygroscopic properties MgCO3 was first added to salt in 1911 to make it flow more freely The Morton Salt company adopted the slogan When it rains it pours meaning that its salt containing MgCO3 would not stick together in humid weather 12 Magnesium carbonate most often referred to as chalk is also used as a drying agent on athletes hands in rock climbing gymnastics weightlifting and other sports in which a firm grip is necessary 8 As a food additive magnesium carbonate is known as E504 Its only known side effect is that it may work as a laxative in high concentrations 13 Magnesium carbonate is used in taxidermy for whitening skulls It can be mixed with hydrogen peroxide to create a paste which is spread on the skull to give it a white finish Magnesium carbonate is used as a matte white coating for projection screens 14 Medical use Edit It is a laxative to loosen the bowels In addition high purity magnesium carbonate is used as an antacid and as an additive in table salt to keep it free flowing Magnesium carbonate can do this because it does not dissolve in water only in acid where it will effervesce bubble 15 Safety EditMagnesium carbonate is non toxic and non flammable Compendial status EditBritish Pharmacopoeia 16 Japanese Pharmacopoeia 17 See also EditCalcium acetate magnesium carbonate Upsalite a reported amorphous form of magnesium carbonateNotes and references Edit a b c d Magnesium carbonate Benezeth Pascale Saldi Giuseppe D Dandurand Jean Louis Schott Jacques 2011 Experimental determination of the solubility product of magnesite at 50 to 200 C Chemical Geology 286 1 2 21 31 Bibcode 2011ChGeo 286 21B doi 10 1016 j chemgeo 2011 04 016 a b Ross Nancy L 1997 The equation of state and high pressure behavior of magnesite Am Mineral 82 7 8 682 688 doi 10 2138 am 1997 7 805 a b Zumdahl Steven S 2009 Chemical Principles 6th Ed Houghton Mifflin Company p A22 ISBN 978 0 618 94690 7 NIOSH Pocket Guide to Chemical Hazards 0373 National Institute for Occupational Safety and Health NIOSH a b c d Margarete Seeger Walter Otto Wilhelm Flick Friedrich Bickelhaupt Otto S Akkerman Magnesium Compounds Ullmann s Encyclopedia of Industrial Chemistry Weinheim Wiley VCH doi 10 1002 14356007 a15 595 pub2 Botha A Strydom C A 2001 Preparation of a magnesium hydroxy carbonate from magnesium hydroxide Hydrometallurgy 62 3 175 doi 10 1016 S0304 386X 01 00197 9 a b Allf Bradley 21 May 2018 The Hidden Environmental Cost of Climbing Chalk Climbing Magazine Cruz Bay Publishing Retrieved 22 May 2018 In fact China produces 70 percent of the world s magnesite Most of that production both mining and processing is concentrated in a small corner of Liaoning a hilly industrial province in northeast China between Beijing and North Korea IAState MSDS Weast Robert C et al 1978 CRC Handbook of Chemistry and Physics 59th ed West Palm Beach FL CRC Press p B 133 ISBN 0 8493 0549 8 a b Conventional and Controlled Rate Thermal analysis of nesquehonite Mg HCO3 OH 2 H2O PDF Her Debut Morton Salt Retrieved 27 December 2017 Food Info net E numbers E504 Magnesium carbonates 080419 food info net Noronha Shonan 2015 Certified Technology Specialist Installation McGraw Hill Education p 256 ISBN 978 0071835657 What Is Magnesium Carbonate Sciencing Retrieved 15 April 2018 British Pharmacopoeia Commission Secretariat 2009 Index BP 2009 PDF Archived from the original PDF on 11 April 2009 Retrieved 31 January 2010 Japanese Pharmacopoeia Fifteenth Edition PDF 2006 Archived from the original PDF on 22 July 2011 Retrieved 31 January 2010 External links Edit Wikimedia Commons has media related to Magnesium carbonate International Chemical Safety Card 0969 NIST Standard Reference Database Retrieved from https en wikipedia org w index php title Magnesium carbonate amp oldid 1125601163, wikipedia, wiki, book, books, library,
