Nickel(II) iodide

Nickel(II) iodide is an inorganic compound with the formula NiI2. This paramagnetic black solid dissolves readily in water to give blue-green solutions of the aquo complexes.[1] This blue-green colour is typical of hydrated nickel(II) compounds. Nickel iodides find some applications in homogeneous catalysis.

Nickel(II) iodide
Nickel(II) iodide hexahydrate, NiI2•6H2O
Nickel(II) iodide
IUPAC name
Nickel(II) iodide
Other names
Nickelous iodide
3D model (JSmol)
ECHA InfoCard 100.033.319
Molar mass 312.5023 g·mol−1
Appearance iron-black solid (anhydrous)
bluish-green solid (hexahydrate)
Density 5.384 g/cm3
Melting point 780 °C (1,440 °F; 1,050 K) (anhydrous)
43 °C (hexahydrate, loses water)
124.2 g/100 mL (0 °C)
188.2 g/100 mL (100 °C)
Solubility alcohols
+3875.0·10−6 cm3/mol
NFPA 704 (fire diamond)
Flammability code 0: Will not burn. E.g. waterHealth code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformReactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no codeNFPA 704 four-colored diamond
Related compounds
Other anions
nickel(II) chloride, nickel(II) bromide, nickel(II) fluoride
Other cations
cobalt iodide, copper iodide,
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

Structure and synthesisEdit

The anhydrous material crystallizes in the CdCl2 motif, featuring octahedral coordination geometry at each Ni(II) center. NiI2 is prepared by dehydration of the pentahydrate.[2]

NiI2 readily hydrates, and the hydrated form can be prepared by dissolution of nickel oxide, hydroxide, or carbonate in hydroiodic acid. The anhydrous form can be produced by treating powdered nickel with iodine.

Applications in catalysisEdit

NiI2 has found some industrial applications as a catalyst in carbonylation reactions.[3] It is also has niche uses as a reagent in organic synthesis, especially in conjunction with samarium(II) iodide.[4]

Like many nickel complexes, those derived from hydrated nickel iodide have been used in cross coupling.[5]

NiI2 as the Ni(II) precatalyst in the aryl iodide and alkyl iodide cross coupling.


  1. ^ Lide, D. R., ed. (2005). CRC Handbook of Chemistry and Physics (86th ed.). Boca Raton (FL): CRC Press. ISBN 0-8493-0486-5.
  2. ^ Ward, Laird G. L. (1972). "Anhydrous Nickel (II) Halides and their Tetrakis(Ethanol) and 1,2-Dimethoxyethane Complexes". Inorganic Syntheses. 13: 154–164. doi:10.1002/9780470132449.ch30.
  3. ^ W. Bertleff, M. Roeper, X. Sava, "Carbonylation" in Ullmann’s Encyclopedia of Industrial Chemistry, Wiley-VCH: Weinheim, 2003. doi:10.1002/14356007.a05_217.
  4. ^ Shinichi Saito, Nickel(II) Iodide" in Encyclopedia of Reagents for Organic Synthesis, John Wiley & Sons, 2008. doi:10.1002/047084289X.rn00843. Article Online Posting Date: March 14, 2008.
  5. ^ Everson, Daniel A.; Shrestha, Ruja; Weix, Daniel J. (2010-01-27). "Nickel-Catalyzed Reductive Cross-Coupling of Aryl Halides with Alkyl Halides". Journal of the American Chemical Society. 132 (3): 920–921. doi:10.1021/ja9093956. PMID 20047282.