Cobalt(II) carbonate

From Wikipedia, the free encyclopedia
Cobalt(II) carbonate
Calcium-carbonate-xtal-3D-SF.png
Cobalt(II) carbonate powder
Names
IUPAC name
Cobalt(II) carbonate
Other names
Cobaltous carbonate; cobalt(II) salt
Identifiers
  • 513-79-1 checkY
  • 12602-23-2 (cobalt carbonate hydroxide) checkY
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.007.428 Edit this at Wikidata
UNII
  • InChI=1S/CH2O3.Co/c2-1(3)4;/h(H2,2,3,4);/q;+2/p-2 ☒N
    Key: ZOTKGJBKKKVBJZ-UHFFFAOYSA-L ☒N
  • InChI=1/CH2O3.Co/c2-1(3)4;/h(H2,2,3,4);/q;+2/p-2
    Key: ZOTKGJBKKKVBJZ-NUQVWONBAB
  • C(=O)([O-])[O-].[Co+2]
Properties
CoCO3
Molar mass 118.941 g/mol
Appearance red/ pink crystals (anhydrous)
pink, violet, red crystalline powder (hexahydrate)
Density 4.13 g/cm3
Melting point 427 °C (801 °F; 700 K) [2]
decomposes before melting to cobalt(II) oxide (anhydrous)
140 °C (284 °F; 413 K)
decomposes (hexahydrate)
Cobalt (II) Carbonate is insoluble in distilled water.
1.0·10−10[1]
Solubility soluble in acid
negligible in alcohol, methyl acetate
insoluble in ethanol
1.855
Structure
Rhombohedral (anhydrous)
Trigonal (hexahydrate)
Thermochemistry
79.9 J/mol·K[2]
Std enthalpy of
formation (ΔfH⦵298)
 −722.6 kJ/mol[2]
Gibbs free energy (ΔfG˚)
 -651 kJ/mol[2]
Hazards
GHS labelling:
GHS07: Exclamation markGHS08: Health hazard[3]
Signal word
 Warning
H302, H315, H317, H319, H335, H351[3]
P261, P280, P305+P351+P338[3]
NFPA 704 (fire diamond)
2
0
0
Lethal dose or concentration (LD, LC):
LD50 (median dose)
 640 mg/kg (oral, rats)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N  (what is checkY☒N ?)
Infobox references

Cobalt(II) carbonate is the inorganic compound with the formula CoCO3. This reddish paramagnetic solid is an intermediate in the hydrometallurgical purification of cobalt from its ores. It is an inorganic pigment, and a precursor to catalysts.[4] Cobalt(II) carbonate also occurs as the rare red/pink mineral spherocobaltite.[5]

Preparation and structure[]

It is prepared by combining solutions cobaltous sulfate and sodium bicarbonate:

CoSO4 + 2 NaHCO3 → CoCO3 + Na2SO4 + H2O + CO2

CoCO3 adopts a structure like calcite, consisting of cobalt in an octahedral coordination geometry.[6]

Reactions[]

Heating the carbonate, proceeds in a typical way for calcining, except that the material is partially oxidized:

6 CoCO3 + O2 → 2 Co3O4 + 6 CO2

The resulting Co3O4 converts reversibly to CoO at high temperatures.[7] Like most transition metal carbonates, cobalt carbonate is insoluble in water, but is readily attacked by mineral acids:

CoCO3 + 2 HCl + 5 H2O → [Co(H2O)6]Cl2 + CO2

It is used to prepare many coordination complexes. The reaction of cobalt(II) carbonate and acetylacetone in the presence of hydrogen peroxide gives tris(acetylacetonato)cobalt(III).[8] These complexes are chiral and often can be resolved into the individual enantiomers.

Uses[]

Cobalt carbonate is a precursor to cobalt carbonyl and various cobalt salts. It is a component of dietary supplements since cobalt is an essential element. It is a precursor to blue pottery glazes, famously in the case of Delftware.

Natural occurrence[]

The moderately rare spherocobaltite is the natural form of cobalt carbonate, with good specimens coming especially from the Republic of Congo. is a cobaltiferous calcite variety that is quite similar in habit to spherocobaltite.[5]

Safety[]

The compound is harmful if swallowed, and irritating to eyes and skin.[clarification needed]

References[]

  1. ^ "Archived copy". Archived from the original on 2012-06-15. Retrieved 2012-05-17.CS1 maint: archived copy as title (link)
  2. ^ a b c d http://chemister.ru/Database/properties-en.php?dbid=1&id=573
  3. ^ a b c Sigma-Aldrich Co., Cobalt(II) carbonate. Retrieved on 2014-05-06.
  4. ^ John Dallas Donaldson, Detmar Beyersmann, "Cobalt and Cobalt Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005. doi:10.1002/14356007.a07_281.pub2
  5. ^ a b "Spherocobaltite: Spherocobaltite mineral information and data". www.mindat.org. Retrieved 7 August 2018.
  6. ^ Pertlik, F. (1986). "Structures of hydrothermally synthesized cobalt(II) carbonate and nickel(II) carbonate". Acta Crystallographica Section C. 42: 4–5. doi:10.1107/S0108270186097524.
  7. ^ G.A. El-Shobaky, A.S. Ahmad, A.N. Al-Noaimi and H.G. El-Shobaky Journal of Thermal Analysis and Calorimetry 1996, Volume 46, Number 6 , pp.1801-1808. online abstract
  8. ^ Bryant, Burl E.; Fernelius, W. Conard (1957). "Cobalt(III) Acetylacetonate". Inorganic Syntheses. pp. 188–189. doi:10.1002/9780470132364.ch53. ISBN 9780470132364.

External links[]

Retrieved from ""