Cobalt(II) acetate

Cobalt(II) acetate is the cobalt salt of acetic acid. It is commonly found as the tetrahydrate Co(CH₃CO₂)₂·4 H₂O, abbreviated Co(OAc)₂·4 H₂O. It is used as a catalyst.

Cobalt(II) acetate

Names
IUPAC name Cobalt(II) acetate
Identifiers
CAS Number	71-48-7 (anhydrous) Y 6147-53-1 (tetrahydrate) Y
3D model (JSmol)	ionic form: Interactive image coordination form (anhydrate): Interactive image coordination form (tetrahydrate): Interactive image
ChemSpider	6041 Y
ECHA InfoCard	100.000.687
PubChem CID	6277
UNII	3XC4P44U7E Y 7648Z91O1N (tetrahydrate) Y
CompTox Dashboard (EPA)	DTXSID6026373
InChI InChI=1S/2C2H4O2.Co/c2*1-2(3)4;/h2*1H3,(H,3,4);/q;;+2/p-2 Y Key: QAHREYKOYSIQPH-UHFFFAOYSA-L Y InChI=1/2C2H4O2.Co/c2*1-2(3)4;/h2*1H3,(H,3,4);/q;;+2/p-2 Key: QAHREYKOYSIQPH-NUQVWONBAX
SMILES ionic form: [Co+2].[O-]C(=O)C.[O-]C(=O)C coordination form (anhydrate): O=C(C)O[Co]OC(C)=O coordination form (tetrahydrate): O=C(C)O[Co-4]([O+H2])([O+H2])([O+H2])([O+H2])OC(C)=O
Properties
Chemical formula	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)
Solubility in water	Soluble
Solubility	soluble in alcohol, dilute acids, pentyl acetate (tetrahydrate)
Magnetic susceptibility (χ)	+11,000·10−6 cm3/mol
Refractive index (nD)	1.542 (tetrahydrate)
Hazards
NFPA 704 (fire diamond)	1 0 0
Lethal dose or concentration (LD, LC):
LD50 (median dose)	503 mg/kg (oral, rat)
Safety data sheet (SDS)	J.T. Baker MSDS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Synthesis and structure

Like many other transition metal acetates, cobalt(II) acetate forms by the reaction of cobalt oxide or hydroxide and acetic acid:

CoO + 2 CH₃CO₂H + 3 H₂O → Co(CH₃CO₂)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] The analogous nickel acetate is isostructural.^[2]

Various hydrates are known including Co(CH₃CO₂)₂·H₂O and [Co(CH₃CO₂)₂]₅·0.5 H₂O.^[3]

Reactions and uses

Cobalt acetate is a precursor to various oil drying agents, catalysts that allow paints and varnishes to harden.^[4]

Anhydrous cobalt acetate is a widely used source of cobalt in the synthesis of materials,^[5] catalyst,^[6] and complexes.^[7]

Oxidation of acetic acid solutions of cobalt(II) acetate, e.g. with ozone, gives cobalt(III) acetates, which are strong oxidants.^[8]

Safety

Cobalt salts are poisonous.^{[citation needed]}