Cobalt(II) acetate

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Cobalt(II) acetate
Cobalt(II) acetate
Names
IUPAC name
Cobalt(II) acetate
Identifiers
3D model (Jmol)
ChemSpider
ECHA InfoCard 100.000.687
UNII
Properties
Co(C2H3O2)2
Molar mass 177.02124 g/mol (anhydrous)
249.08 g/mol (tetrahydrate)
Appearance Pink crystals (anhydrous)
intense red crystals (tetrahydrate)
Odor vinegar (tetrahydrate)
Density 1.705 g/cm3 (tetrahydrate)
Melting point 140 °C (284 °F; 413 K) (tetrahydrate)
Soluble
Solubility soluble in alcohol, dilute acids, pentyl acetate (tetrahydrate)
+11,000·10−6 cm3/mol
1.542 (tetrahydrate)
Hazards
Safety data sheet J.T. Baker MSDS
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
Lethal dose or concentration (LD, LC):
503 mg/kg (oral, rat)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Cobalt(II) acetate is the cobalt(II) salt of acetic acid. It is commonly found as the tetrahydrate Co(C2H3O2)2·4 H2O or Co(CH3COO)2·4 H2O also abbreviated Co(OAc)2·4 H2O. It is used as an industrial catalyst.

Synthesis and structure[edit]

It may be formed by the reaction between cobalt oxide or hydroxide and acetic acid:

CoO + 2 HC2H3O2 + 3 H2O → Co(C2H3O2)2·4 H2O

The tetrahydrate has been shown by X-ray crystallography to adopt an octahedral structure, the central cobalt centre being coordinated by four water molecules and two acetate ligands.[1]

Reactions and uses[edit]

Cobalt acetate is a precursor to various oil drying agents, catalysts that allow paints and varnishes to harden.[2] Cobalt(II) acetate reacts with salenH2 to give salcomine, a transition metal dioxygen complex:[3]

Co(OAc)2 + salenH2 → Co(salen) + 2 HOAc

Safety[edit]

Cobalt salts are poisonous.[4]

References[edit]

  1. ^ Van Niekerk, J. N.; Schoening, F. R. L. (1953). "The crystal structures of nickel acetate, Ni(CH3COO)2·4H2O, and cobalt acetate, Co(CH3COO)2·4H2O". Acta Crystallogr. 6 (7): 609–612. doi:10.1107/S0365110X5300171X. 
  2. ^ 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
  3. ^ Appleton, T. G. (1977). "Oxygen Uptake by a Cobalt(II) Complex". J. Chem. Ed. 54 (7): 443. doi:10.1021/ed054p443. 
  4. ^ MallBaker MSDS