Fluoronickelate
Class of chemical compounds
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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.
| formula | name | Ni Ox | structure | Remarks | references |
|---|---|---|---|---|---|
| (NH4)2NiF4 | ammonium tetrafluoronickelate | 2 | Fuse NiCl2 with NH4F, light green color | [1][2] | |
| (NH4)2NiF4·2H2O | ammonium tetrafluoronickelate dihydrate | 2 | Formed from Ni(OH)2 and NH4F in water | [3] | |
| K2NiF4 | potassium tetrafluoronickelate | 2 | [1] | ||
| Rb2NiF4 | rubidium tetrafluoronickelate | 2 | [1] | ||
| Ba2NiF6 | barium nickel fluoride | 2 | yellow square plates cas=18115-49-6 | [4] | |
| Pb2NiF6 | lead(II)nickel(II) fluoride | 2 | cas=27037-78-1 | [4] | |
| Li3NiF6 | 3 | Pna2 C92v a=9.60 Å b=8.37 Å c=4.09 Å Z=4 density=3.27 / 3.24 | formed at 500° 70 bar F2 | [5][6] | |
| Na3NiF6 | sodium hexafluoronickelate | 3 | violet cas=22707-99-9 | [4] | |
| K3NiF6 | potassium hexafluoronickelate | 3 | violet cas=14881-07-3 | [4][7] | |
| KCs2NiF6 | dicesium potassium hexafluoronickelate | 3 | lilac colour cas=53479-35-9 | [4] | |
| Li2NiF6 | lithium hexafluoronickelate | 4 | hexagonal a=8.321 Å c=4.598 Å V=275.7 Å3 Z=3 | pink sol 0.5 g/100 g HF at 0° | [5][7] |
| (O2)2NiF6 | dioxygenyl hexafluoronickelate | possibly existing, decompose 10° | [8][9] | ||
| (NO2)2NiF6 | dinitronium hexafluoronickelate | 4 | ΔH=-471 kJ/mol, ΔH0f=-1120 | [10] | |
| Na2NiF6 | sodium hexafluoronickelate | 4 | cubic; or tetragonal | purple red | [11] |
| K2NiF6 | potassium hexafluoronickelate | 4 | K2PtCl6 structure | red cas=17218-47-2 | [11] |
| CaNiF6 | calcium hexafluoronickelate | 4 | ΔH=-363 kJ/mol, ΔH0f=-1951 kJ/mol sold as a fluorine source | [10] | |
| Rb2NiF6 | rubidium hexafluoronickelate | 4 | K2PtCl6 structure | red cas=17218-48-3 | [11] |
| Cs2NiF6 | Cesium hexafluoronickelate | 4 | K2PtCl6 structure | red cas=17218-49-4 | [11] |
| SrNiF6 | strontium hexafluoronickelate | 4 | red cas=66456-12-0 | [11] | |
| BaNiF6 | barium hexafluoronickelate | 4 | K2PtCl6 structure | red cas=66456-13-1 | [11] |
| (NF4)2NiF6 | bis-tetrafluoroammonium hexafluoronickelate | 4 | tetragonal K2PtCl6 structure | red cas=63105-40-8 | [11] |
| (ClF2O)NiF6 | bis [difluorooxychlorine (V)] hexafluoronickelate (IV) | 4 | deep purple, stable to 60 °C | [12][13] |