Formula BiF3 Density 5.32 g/cm³ Appearance grey-white powder | Molar mass 265.9755 g/mol Boiling point 900 °C | |
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Bismuth trifluoride is a chemical compound of bismuth and fluorine. The chemical formula is BiF3. It is a grey-white powder melting at 649°C.
Contents
Synthesis
Bismuth trifluoride can be prepared by reacting bismuth(III) oxide with hydrofluoric acid:
Bi2O3 + 6 HF → 2 BiF3 + 3 H2OStructure
α-BiF3 has a cubic crystalline structure (Pearson symbol cF16, space group Fm-3m, No. 225). β-BiF3 has the YF3 structure where the bismuth atom has distorted 9 coordination, tricapped trigonal prism. This structure is generally considered to be ionic, and contrasts with fluorides of the lighter members of group 5, phosphorus trifluoride, PF3, arsenic trifluoride, AsF3 and antimony trifluoride, SbF3, where MX3 molecular units are present in the solid.
Reactions
BiF3 is unaffected by water and is almost insoluble. It does not form complexes readily but the following, BiF3.3HF and BiF4− in NH4BiF4, are known. The addition compound H3BiF6 is hydrolysed by water forming BiOF.