Fluoronickelate

The fluoronickelates are a class of chemical compounds containing an anion with nickel at its core, surrounded by fluoride ions which act as ligands. This makes it a fluoroanion. The nickel atom can be in a range of oxidation states from +2, +3 to +4. The hexafluoronickelate(IV)2− ion NiF62− contains nickel in the maximal +4 state, and is in octahedral coordination by the fluoride atoms. It forms a commercially available salt Potassium hexafluoronickelate(IV) K2NiF6. Solid double salts can also contain tetrafluoronickelate NiF4 eg K2NiF4.

formulanameNi OxstructureRemarksreferences(NH4)2NiF4ammonium tetrafluoronickelate2Fuse NiCl2 with NH4F, light green colorHandbook of inorganic substances 2017(NH4)2NiF4·2H2Oammonium tetrafluoronickelate dihydrate2Formed from Ni(OH)2 and NH4F in waterK2NiF4potassium tetrafluoronickelate2Rb2NiF4rubidium tetrafluoronickelate2Ba2NiF6barium nickel fluoride2yellow square plates cas=18115-49-6Pb2NiF6lead(II)nickel(II) fluoride2cas=27037-78-1Li3NiF63Pna2 C92v a=9.60 Å b=8.37 Å c=4.09 Å Z=4 density=3.27 / 3.24formed at 500° 70 bar F2Na3NiF6sodium hexafluoronickelate3violet cas=22707-99-9K3NiF6potassium hexafluoronickelate3violet cas=14881-07-3KCs2NiF6dicesium potassium hexafluoronickelate3lilac colour cas=53479-35-9Li2NiF6lithium hexafluoronickelate4hexagonal a=8.321 Å c=4.598 Å V=275.7 Å3 Z=3pink sol 0.5 g/100 g HF at 0°(O2)2NiF6dioxygenyl hexafluoronickelatepossibly existing, decompose 10°(NO2)2NiF6dinitronium hexafluoronickelate4ΔH=-471 kJ/mol, ΔH0f=-1120Na2NiF6sodium hexafluoronickelate4cubic; or tetragonalpurple redK2NiF6potassium hexafluoronickelate4K2PtCl6 structurered cas=17218-47-2CaNiF6calcium hexafluoronickelate4ΔH=-363 kJ/mol, ΔH0f=-1951 kJ/mol sold as a fluorine sourceRb2NiF6rubidium hexafluoronickelate4K2PtCl6 structure red cas=17218-48-3Cs2NiF6Cesium hexafluoronickelate4K2PtCl6 structurered cas=17218-49-4SrNiF6strontium hexafluoronickelate4 red cas=66456-12-0BaNiF6barium hexafluoronickelate4K2PtCl6 structure red cas=66456-13-1(NF4)2NiF6bis-tetrafluoroammonium hexafluoronickelate4tetragonal K2PtCl6 structure red cas=63105-40-8(ClF2O)NiF6bis [difluorooxychlorine (V)] hexafluoronickelate (IV)4deep purple, stable to 60 °C

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