Nickel(II) acetate

Nickel(II) acetate is the name for the coordination compounds with the formula Ni(CH3CO2)2·x H2O where x can be 0, 2, and 4. The green tetrahydrate Ni(CH3CO2)2·4 H2O is most common. It is used for electroplating.

Nickel(II) acetate
Names
Systematic IUPAC name
Nickel(2+) diacetate
Identifiers
3D model (JSmol)
ECHA InfoCard 100.006.147
EC Number
  • 239-086-1
UNII
  • InChI=1S/2C2H4O2.Ni/c2*1-2(3)4;/h2*1H3,(H,3,4);/q;;+2/p-2
  • ionic form: [Ni+2].[O-]C(=O)C.[O-]C(=O)C
  • coordination form (anhydrate): O=C(C)O[Ni]OC(C)=O
  • coordination form (tetrahydrate): O=C(C)O[Ni-4](OC(C)=O)([O+H2])([O+H2])([O+H2])[O+H2]
Properties
C4H6NiO4
Molar mass 176.781 g·mol−1
Appearance Green Solid
Odor slight acetic acid
Density 1.798 g/cm3 (anhydrous)
1.744 g/cm3 (tetrahydrate)
Melting point decomposes when heated [1][2]
Easily soluble in cold water, hot water
Solubility Soluble in methanol
insoluble in diethyl ether, n-octanol
+4,690.0·10−6 cm3/mol
Structure
monoclinic
P21/c
a = 4.764, b = 11.771, c = 8.425 Å
α = 90°, β = 93.6°, γ = 90°[3]
tetrahydrate
471.5
2
distorted octahedral
Hazards
NFPA 704 (fire diamond)
NFPA 704 four-colored diamond
2
0
0
Lethal dose or concentration (LD, LC):
350 mg/kg (rat, oral)
410 mg/kg (mouse, oral)[4]
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

Synthesis and structure

The compound can be prepared by treating nickel or nickel(II) carbonate with acetic acid:

NiCO3 + 2 CH3CO2H + 3 H2O → Ni(CH3CO2)2·4 H2O + CO2

The green tetrahydrate has been shown by X-ray crystallography to adopt an octahedral structure, the central nickel centre being coordinated by four water molecules and two acetate ligands.[5] It may be dehydrated in vacuo, by reaction with acetic anhydride[6] or by heat.[7]

Safety

Nickel salts are carcinogenic and irritate the skin.

References
  1. M. A. Mohamed, S. A. Halawy, M. M. Ebrahim: "Non-isothermal decomposition of nickel acetate tetrahydrate", in: Journal of Analytical and Applied Pyrolysis, 1993, 27 (2), S. 109–110. doi:10.1016/0165-2370(93)80002-H.
  2. G. A. M. Hussein, A. K. H. Nohman, K. M. A. Attyia: "Characterization of the decomposition course of nickel acetate tetrahydrate in air", in: Journal of Thermal Analysis and Calorimetry, 1994, 42, S. 1155–1165; doi:10.1007/BF02546925.
  3. Downie, T. C.; Harrison, W.; Raper, E. S.; Hepworth, M. A. (15 March 1971). "A three-dimensional study of the crystal structure of nickel acetate tetrahydrate". Acta Crystallographica Section B. 27 (3): 706–712. doi:10.1107/S0567740871002802.
  4. "Nickel metal and other compounds (as Ni)". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  5. 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.
  6. Lascelles, Keith; Morgan, Lindsay G.; Nicholls, David; Beyersmann, Detmar (2005). "Nickel Compounds". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a17_235.pub2.
  7. Tappmeyer, W. P.; Davidson, Arthur W. (1963). "Cobalt and Nickel Acetates in Anhydrous Acetic Acid". Inorg. Chem. 2 (4): 823–825. doi:10.1021/ic50008a039.
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