Cobalt(II) acetate

Cobalt(II) acetate
Names
IUPAC name
Cobalt(II) acetate
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.000.687 Edit this at Wikidata
UNII
  • InChI=1S/2C2H4O2.Co/c2*1-2(3)4;/h2*1H3,(H,3,4);/q;;+2/p-2 checkY
    Key: QAHREYKOYSIQPH-UHFFFAOYSA-L checkY
  • InChI=1/2C2H4O2.Co/c2*1-2(3)4;/h2*1H3,(H,3,4);/q;;+2/p-2
    Key: QAHREYKOYSIQPH-NUQVWONBAX
  • 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
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
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineFlammability 0: Will not burn. E.g. waterInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
1
0
0
Lethal dose or concentration (LD, LC):
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).
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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.

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]

References

  1. ^ Sobolev, Alexandre N.; Miminoshvili, Elguja B.; Miminoshvili, Ketevan E.; Sakvarelidze, Tamara N. (2003). "Cobalt diacetate tetrahydrate". Acta Crystallographica Section E. 59 (10): m836 – m837. doi:10.1107/S1600536803019093.
  2. ^ 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.
  3. ^ Zhang, Gao; Lin, Jian; Guo, Dong-Wei; Yao, Shi-Yan; Tian, Yun-Qi (2010). "Infinite Coordination Polymers of One- and Two-dimensional Cobalt Acetates". Zeitschrift für Anorganische und Allgemeine Chemie. 636 (7): 1401–1404. doi:10.1002/zaac.200900457.
  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. ^ Rodenas, Tania; Luz, Ignacio; Prieto, Gonzalo; Seoane, Beatriz; Miro, Hozanna; Corma, Avelino; Kapteijn, Freek; Llabrés i Xamena, Francesc X.; Gascon, Jorge (2015). "Metal–organic framework nanosheets in polymer composite materials for gas separation". Nature Materials. 14 (1): 48–55. Bibcode:2015NatMa..14...48R. doi:10.1038/nmat4113. PMC 4270742. PMID 25362353.
  6. ^ Schultz, Mitchell J.; Sigman, Matthew S. (2006). "Recent advances in homogeneous transition metal-catalyzed aerobic alcohol oxidations". Tetrahedron. 62 (35): 8227–8241. doi:10.1016/j.tet.2006.06.065.
  7. ^ Appleton, T. G. (1977). "Oxygen Uptake by a Cobalt(II) Complex". J. Chem. Educ. 54 (7): 443. doi:10.1021/ed054p443.
  8. ^ Periasamy, Mariappan; Radhakrishnan, Ukkiramapandian (2001). "Cobalt(III) Acetate". Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rc188. ISBN 0-471-93623-5.

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