Bismuth pentafluoride


Bismuth pentafluoride is an inorganic compound with the formula BiF5. It is a white solid that is highly reactive. The compound is of interest to researchers but not of particular value.

Structure

BiF5 is polymeric and consists of linear chains of trans-bridged corner sharing BiF6 octahedra. This is the same structure as α-UF5.


∞ chain
packing of chains

Preparation

BiF5 can be prepared by treating BiF3 with F2 at 500 °C.
In an alternative synthesis, ClF3 is the fluorinating agent at 350 °C.

Reactions

Bismuth pentafluoride is the most reactive of the pnictogen pentafluorides and is an extremely strong fluorinating agent. It reacts vigorously with water to form ozone and oxygen difluoride, and with iodine or sulfur at room temperature. BiF5 fluorinates paraffin oil to fluorocarbons above 50 °C and oxidises UF4 to UF6 at 150 °C. At 180 °C, bismuth pentafluoride fluorinates Br2 to BrF3 and Cl2 to ClF.
BiF5 also reacts with alkali metal fluorides, MF, to form hexafluorobismuthates, M, containing the hexafluorobismuthate anion, −.