Cobalt(II) carbonate

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Cobalt(II) carbonate
Thermal ellipsoid model of the unit cell of cobalt(II) carbonate Cobalt(II) carbonate powder
Identifiers
CAS number 513-79-1 N
12602-23-2 (cobalt carbonate hydroxide)
PubChem 10565
Properties
Molecular formula CCoO3
Molar mass 118.94 g mol−1
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)
Solubility in water negligible
Solubility product, Ksp 1.0·10-10[1]
Solubility soluble in acid
negligible in alcohol, methyl acetate
insoluble in ethanol
Refractive index (nD) 1.855
Structure
Crystal structure Rhombohedral (anhydrous)
Trigonal (hexahydrate)
Thermochemistry
Std molar
entropy
So298
79.9 J/mol·K[2]
Std enthalpy of
formation
ΔfHo298
−722.6 kJ/mol[2]
Gibbs free energy ΔG -651 kJ/mol[2]
Hazards
GHS pictograms The exclamation-mark pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)The health hazard pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)[3]
GHS signal word Warning
GHS hazard statements H302, H315, H317, H319, H335, H351[3]
GHS precautionary statements P261, P280, P305+351+338[3]
EU classification Harmful Xn
R-phrases R22, R36/37/38, R40, R43
S-phrases S26, S36/37
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 1: Exposure would cause irritation but only minor residual injury. E.g., turpentine Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
LD50 640 mg/kg (oral, rats)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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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] Commercially available pale violet basic cobalt carbonate, with the formula CoCO3(Co(OH)x(H2O)y (CAS 12069-68-0).[5]

Preparation and properties[edit]

It is prepared by heating cobaltous sulfate with a solution of sodium bicarbonate.

Heating the carbonate, i.e. calcining, proceeds in the usual way:

3 CoCO3 + 1/2 O2 → Co3O4 + 3 CO2

The resulting Co3O4 converts reversibly to CoO at high temperatures.[6] 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

Uses[edit]

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.

Safety[edit]

The compound is harmful if swallowed, and irritating to eyes and skin.

References[edit]

  1. ^ http://www.ktf-split.hr/periodni/en/abc/kpt.html
  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. ^ Cobalt(II) carbonate also occurs as the rare mineral spherocobaltite, which occurs as pink/red trigonal crystals with a specific gravity of 4.13g/cm3Spherocobaltite www.mindat.org
  6. ^ 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

External links[edit]


H2CO3 He
Li2CO3 BeCO3 B C N O F Ne
Na2CO3 MgCO3 Al2(CO3)3 Si P S Cl Ar
K2CO3 CaCO3 Sc Ti V Cr MnCO3 FeCO3 CoCO3 NiCO3 CuCO3 ZnCO3 Ga Ge As Se Br Kr
Rb2CO3 SrCO3 Y Zr Nb Mo Tc Ru Rh Pd Ag2CO3 CdCO3 In Sn Sb Te I Xe
Cs2CO3 BaCO3 Hf Ta W Re Os Ir Pt Au Hg Tl2CO3 PbCO3 Bi Po At Rn
Fr Ra Rf Db Sg Bh Hs Mt Ds Rg Cn Uut Fl Uup Lv Uus Uuo
La2(CO3)3 Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr