四氯镍酸根

四氯镍酸根离子是一种金属配合物，化学式为[NiCl₄]²⁻，其盐称作四氯镍酸盐。四氯镍酸根离子可以与各种各样的阳离子键合，但常见的包括四乙基铵阳离子。^[1]

当浓氯化锂和氯化镍的水溶液混合在一起时，它们只会形成五水氯络合物：[Ni(H₂O)₅Cl]⁺。然而，在其他有机溶剂或熔融的盐中，它们可以形成四氯镍酸根离子。如果将镍配分到胺的环己烷溶液中，镍就可以从这些盐的水或甲醇溶液中被分离出来。^[2]

(R₃NH)₂[NiCl₄]之类的有机铵盐通常可以发生热致变色（R = Me, Et, Pr）。在近室温的环境下，这些盐呈黄色，但它们在70 °C下会变成蓝色。亮蓝色是四面体的[NiCl₄]²⁻的特征，而强度是拉波特规则导致的。盐呈黄色是因为它们生成了由八面体Ni中心组成的聚合物。相应的四溴镍酸盐在较低的温度下也会发生热致变色的。^[3]

历史

1944年，Remy和Meyer将氯化铯和三氯化铯镍一起熔化时，首次观察到由四氯镍酸根离子引起的蓝色。^[4]

化合物

公式	名称	结构	备注	参考
Cs₂NiCl₄	四氯镍酸铯		只在超过70 °C的环境下保持蓝色	^[4]
[(CH₃)₄N]₂NiCl₄	四甲基四氯镍酸铵		深蓝色	^[5]
[(C₂H₅)₄N]₂NiCl₄	四乙基四氯镍酸铵（英语：Tetraethylammonium tetrachloronickelate）			^[6] ^[4]
[H₂NN(CH₃)₃]₂NiCl₄	1,1,1-三甲基肼正离子四氯镍盐（1,1,1-三甲基四氯镍酸𰽟）		只在超过145 °C的环境下保持蓝色，在此温度以下呈黄色	^[7]
[(C₆H₅)₄As]₂NiCl₄	双四苯基砷正离子（𬭩）四氯镍酸盐		蓝色，熔点199.5 °C	^[5]
[(C₆H₅)₃CH₃As]₂NiCl₄	双三苯甲基砷正离子（𬭩）四氯镍酸盐		蓝色	^[4]
[C₂mim]₂NiCl₄	1-乙基-3-甲基咪唑正离子（𬭩）四氯镍(II)酸盐	四方晶系，I4₁/a a=14.112，c=19.436，V=3871.1，Z=8，密度=1.47，MW=422.84	熔点92 °C	^[8] ^[9]
[C₄mim]₂NiCl₄	1-丁基-3-甲基咪唑正离子（𬭩）四氯镍(II)酸盐	深蓝色，熔点56 °C		^[8]
[C₅mim]₂NiCl₄	1-戊基-3-甲基咪唑正离子（𬭩）四氯镍(II)酸盐	深蓝色液体		^[8]
[C₆mim]₂NiCl₄	1-己基-3-甲基咪唑正离子（𬭩）四氯镍(II)酸盐	深蓝色液体		^[8]
[C₇mim]₂NiCl₄	1-庚基-3-甲基咪唑正离子（𬭩）四氯镍(II)酸盐	深蓝色液体		^[8]
[C₈mim]₂NiCl₄	1-辛基-3-甲基咪唑正离子（𬭩）四氯镍(II)酸盐	深蓝色液体		^[8]
[NH₃CH₂CH₂NH₃]NiCl₄	乙二胺正离子四氯镍(II)酸盐	钙钛矿层状，空间群P2₁/c a=8.441，b=6.995，c=6.943，β=92.925，Z=2	棕色，与Mn、Cu、Pd和Cd化合物同构	^[10]

有关物质

四溴镍酸根（英语：tetrabromonickelates）

参考文献

^ Naida S. Gill; F. B. Taylor. Tetrahalo Complexes of Dipositive Metals in the First Transition Series. Inorganic Syntheses 9. 1967: 136–142. ISBN 978-0-470-13240-1. doi:10.1002/9780470132401.ch37.
^ Florence, T. M.; Farrar, Yvonne J. Liquid-liquid extraction of nickel with long-chain amines from aqueous and nonaqueous halide media. Analytical Chemistry. July 1968, 40 (8): 1200–1206. doi:10.1021/ac60264a010.
^ Ferraro, John R.; Sheren, Anne T. Some new thermochromic complexes of Nickel(II) of the type [R/sub x/NH/sub 4-x/]2NiCl4. Inorganic Chemistry. 3 February 1978, 17 (9): 2498–2502. doi:10.1021/ic50187a032.
^ ^4.0 ^4.1 ^4.2 ^4.3 Gill, Naida S.; Nyholm, R. S. 802. Complex halides of the transition metals. Part I. Tetrahedral nickel complexes. Journal of the Chemical Society (Resumed). 1959: 3997. doi:10.1039/JR9590003997. Gill, Naida S.; Nyholm, R. S. (1959). "802. Complex halides of the transition metals. Part I. Tetrahedral nickel complexes". Journal of the Chemical Society (Resumed): 3997. doi:10.1039/JR9590003997.
^ ^5.0 ^5.1 Cotton, F. A.; Faut, O. D.; Goodgame, D. M. L. Preparation, Spectra and Electronic Structures of Tetrahedral Nickel(II) Complexes Containing Triphenylphosphine and Halide Ions as Ligands. Journal of the American Chemical Society. January 1961, 83 (2): 344–351. doi:10.1021/ja01463a021.
^ Inman, Guy W.; Hatfield, William E.; Jones, Edwin R. The magnetic properties of tetraethylammonium tetrachloronickelate(II) and tetraethylammonium tetrabromonickelate(II). Inorganic and Nuclear Chemistry Letters. August 1971, 7 (8): 721–723. doi:10.1016/0020-1650(71)80078-8.
^ Goedken, V. L.; Vallarino, L. M.; Quagliano, J. V. Cationic ligands. Coordination of the 1,1,1-trimethylhydrazinium cation to nickel(II). Inorganic Chemistry. December 1971, 10 (12): 2682–2685. doi:10.1021/ic50106a011.
^ ^8.0 ^8.1 ^8.2 ^8.3 ^8.4 ^8.5 Meredith, M. Brett; McMillen, C. Heather; Goodman, Jonathan T.; Hanusa, Timothy P. Ambient temperature imidazolium-based ionic liquids with tetrachloronickelate(II) anions. Polyhedron. August 2009, 28 (12): 2355–2358. doi:10.1016/j.poly.2009.04.037.
^ Hitchcock, Peter B.; Seddon, Kenneth R.; Welton, Thomas. Hydrogen-bond acceptor abilities of tetrachlorometalate(II) complexes in ionic liquids. Journal of the Chemical Society, Dalton Transactions. 1993, (17): 2639. doi:10.1039/DT9930002639.
^ Skaarup, Steen; Berg, Rolf Willestofte. Structural properties and vibrational spectra of the ethylene-diammonium family of perovskite layer-type crystals: [NH3CH2CH2NH3] [MCl4], M = Ni, Pd, Cu, Cd, Mn. Journal of Solid State Chemistry. September 1978, 26 (1): 59–67. Bibcode:1978JSSCh..26...59S. doi:10.1016/0022-4596(78)90133-0.

[1] Naida S. Gill; F. B. Taylor. Tetrahalo Complexes of Dipositive Metals in the First Transition Series. Inorganic Syntheses 9. 1967: 136–142. ISBN 978-0-470-13240-1. doi:10.1002/9780470132401.ch37.

[2] Florence, T. M.; Farrar, Yvonne J. Liquid-liquid extraction of nickel with long-chain amines from aqueous and nonaqueous halide media. Analytical Chemistry. July 1968, 40 (8): 1200–1206. doi:10.1021/ac60264a010.

[Ferr-3] Ferraro, John R.; Sheren, Anne T. Some new thermochromic complexes of Nickel(II) of the type [R/sub x/NH/sub 4-x/]2NiCl4. Inorganic Chemistry. 3 February 1978, 17 (9): 2498–2502. doi:10.1021/ic50187a032.

[Gill-4] 4.0 ^4.1 ^4.2 ^4.3 Gill, Naida S.; Nyholm, R. S. 802. Complex halides of the transition metals. Part I. Tetrahedral nickel complexes. Journal of the Chemical Society (Resumed). 1959: 3997. doi:10.1039/JR9590003997. Gill, Naida S.; Nyholm, R. S. (1959). "802. Complex halides of the transition metals. Part I. Tetrahedral nickel complexes". Journal of the Chemical Society (Resumed): 3997. doi:10.1039/JR9590003997.

[cot-5] 5.0 ^5.1 Cotton, F. A.; Faut, O. D.; Goodgame, D. M. L. Preparation, Spectra and Electronic Structures of Tetrahedral Nickel(II) Complexes Containing Triphenylphosphine and Halide Ions as Ligands. Journal of the American Chemical Society. January 1961, 83 (2): 344–351. doi:10.1021/ja01463a021.

[6] Inman, Guy W.; Hatfield, William E.; Jones, Edwin R. The magnetic properties of tetraethylammonium tetrachloronickelate(II) and tetraethylammonium tetrabromonickelate(II). Inorganic and Nuclear Chemistry Letters. August 1971, 7 (8): 721–723. doi:10.1016/0020-1650(71)80078-8.

[7] Goedken, V. L.; Vallarino, L. M.; Quagliano, J. V. Cationic ligands. Coordination of the 1,1,1-trimethylhydrazinium cation to nickel(II). Inorganic Chemistry. December 1971, 10 (12): 2682–2685. doi:10.1021/ic50106a011.

[Meredith-8] 8.0 ^8.1 ^8.2 ^8.3 ^8.4 ^8.5 Meredith, M. Brett; McMillen, C. Heather; Goodman, Jonathan T.; Hanusa, Timothy P. Ambient temperature imidazolium-based ionic liquids with tetrachloronickelate(II) anions. Polyhedron. August 2009, 28 (12): 2355–2358. doi:10.1016/j.poly.2009.04.037.

[9] Hitchcock, Peter B.; Seddon, Kenneth R.; Welton, Thomas. Hydrogen-bond acceptor abilities of tetrachlorometalate(II) complexes in ionic liquids. Journal of the Chemical Society, Dalton Transactions. 1993, (17): 2639. doi:10.1039/DT9930002639.

[10] Skaarup, Steen; Berg, Rolf Willestofte. Structural properties and vibrational spectra of the ethylene-diammonium family of perovskite layer-type crystals: [NH3CH2CH2NH3] [MCl4], M = Ni, Pd, Cu, Cd, Mn. Journal of Solid State Chemistry. September 1978, 26 (1): 59–67. Bibcode:1978JSSCh..26...59S. doi:10.1016/0022-4596(78)90133-0.

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