Tetrachloronickelate
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Tetrachloronickelates are a class of chemical compounds containing anions consisting of a nickel atom surrounded by four chloride ions.
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Substituted ammonia tetrachloronickelates can be thermochromic. At room temperature they can be in a polymeric yellow coloured form, but when heated become bright blue, as the form changes to a tetrahedral arrangement of chlorine around the nickel atom.[1] Yet other amine salts of tetrachloronickelate, such as [(NC3H7)3NH]2NiCl4, are blue liquids at room temperature.[1] The trimethylammonium and diethylammonium salts have thermochromic temperatures at 70 °C. The corresponding tetrabromonickelates are also thermochromic with a transition at lower temperatures.[1]
Some tetrachloronickelates can be ionic liquids at room temperature.
| formula | name | Ni Ox | structure | Remarks | references |
|---|---|---|---|---|---|
| [C2mim]2NiCl4 | 1-ethyl-3-methylimidazolium tetrachloronickelate(II) | 2 | tetragonal I41/a a=14.112 c=19.436 V=3871.1 Z=8 density=1.47 MW=422.84 | melt 92° | [2][3] |
| [C4mim]2NiCl4 | 1-butyl-3-methylimidazolium tetrachloronickelate(II) | 2 | dark blue melt 56° | [2] | |
| [C5mim]2NiCl4 | 1-pentyl-3-methylimidazolium tetrachloronickelate(II) | 2 | dark blue liquid | [2] | |
| [C6mim]2NiCl4 | 1-hexyl-3-methylimidazolium tetrachloronickelate(II) | 2 | dark blue liquid | [2] | |
| [C7mim]2NiCl4 | 1-heptyl-3-methylimidazolium tetrachloronickelate(II) | 2 | dark blue liquid | [2] | |
| [C8mim]2NiCl4 | 1-octyl-3-methylimidazolium tetrachloronickelate(II) | 2 | dark blue liquid | [2] |
References
- ^ a b c Ferraro, John R.; Sheren, Anne T. (3 February 1978). "Some new thermochromic complexes of Nickel(II) of the type [R/sub x/NH/sub 4-x/]2NiCl4". Inorganic Chemistry. 17 (9): 2798–2502. doi:10.1021/ic50187a032.
- ^ a b c d e f Meredith, M. Brett; McMillen, C. Heather; Goodman, Jonathan T.; Hanusa, Timothy P. (August 2009). "Ambient temperature imidazolium-based ionic liquids with tetrachloronickelate(II) anions". Polyhedron. 28 (12): 2355–2358. doi:10.1016/j.poly.2009.04.037.
- ^ Hitchcock, Peter B.; Seddon, Kenneth R.; Welton, Thomas (1993). "Hydrogen-bond acceptor abilities of tetrachlorometalate(II) complexes in ionic liquids". Journal of the Chemical Society, Dalton Transactions (17): 2639. doi:10.1039/DT9930002639.