Cobalt(II) carbonate

Preparation and structure

:left|thumb|Structure of solid cobalt(II) carbonate shown with space-filling ions. Color code: red = O, green = Co, blck = C|220px It is prepared by combining solutions of cobalt(II) sulfate and sodium bicarbonate: :CoSO4 + 2 NaHCO3 → CoCO3 + Na2SO4 + H2O + CO2 This reaction is used in the precipitation of cobalt from an extract of its roasted ores.

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

Reactions

Aqueous solutions of cobalt chloride can be prepared from cobalt(II) carbonate with hydrochloric acid according to this idealized equation: :

The reaction of cobalt(II) carbonate and acetylacetone in the presence of hydrogen peroxide gives tris(acetylacetonato)cobalt(III).

Heating the carbonate in air (calcining) is accompanied by partial oxidation: : 6CoCO3 + O2 → 2Co3O4 + 6CO2 The resulting Co3O4 converts reversibly to CoO at high temperatures.

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.

Related compounds

At least two cobalt(II) carbonate-hydroxides are known: Co2(CO3)(OH)2 and Co6(CO3)2(OH)8·H2O.

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

Sodium tris(carbonato)cobalt(III) is a cobalt(III) complex containing three carbonate ligands.

Safety

Toxicity has rarely been observed. Animals, including humans, require trace amounts of cobalt, a component of vitamin B12.

References

References

1. (2017). "CRC Handbook of Chemistry and Physics". CRC Press, Taylor & Francis Group.
2. "Solubility product constants".
3. "Cobalt(II) carbonate".
4. {{Sigma-Aldrich
5. (2005). "Cobalt and Cobalt Compounds".
6. "Spherocobaltite: Spherocobaltite mineral information and data".
7. Pertlik, F.. (1986). "Structures of hydrothermally synthesized cobalt(II) carbonate and nickel(II) carbonate". Acta Crystallographica Section C.
8. (1963). "Handbook of Preparative Inorganic Chemistry, 2nd Ed.". Academic Press.
9. (1957). "Inorganic Syntheses".
10. (1996). "Thermal Decomposition of Basic Cobalt and Copper Carbonates". Journal of Thermal Analysis and Calorimetry.
11. (2019). "A Quarter of a Century After its Synthesis and with >200 Papers Based on its Use, 'Co(CO₃)_0.5(OH)_0.11H₂O′ Proves to be Co₆(CO₃)₂(OH)₈·H₂O from Synchrotron Powder Diffraction Data". Acta Crystallographica Section C: Structural Chemistry.