Bromine trifluoride


Bromine trifluoride is an interhalogen compound with the formula BrF3. It is a straw-coloured liquid with a pungent odor. It is soluble in sulfuric acid but reacts violently with water and organic compounds. It is a powerful fluorinating agent and an ionizing inorganic solvent. It is used to produce uranium hexafluoride in the processing and reprocessing of nuclear fuel.

Synthesis

Bromine trifluoride was first described by Paul Lebeau in 1906, who obtained the material by the reaction of bromine with fluorine at 20 °C:
The disproportionation of bromine monofluoride also gives bromine trifluoride:

Structure

Like ClF3 and IF3, the BrF3 molecule is T-shaped and planar. In the VSEPR formalism, the bromine center is assigned two electron pairs. The distance from the bromine each axial fluorine is 1.81 Å and to the equatorial fluorine is 1.72 Å. The angle between an axial fluorine and the equatorial fluorine is slightly smaller than 90° — the 86.2° angle observed is due to the repulsion generated by the electron pairs being greater than that of the Br-F bonds.

Chemical properties

BrF3 rapidly and exothermically reacts with water to release hydrobromic acid and hydrofluoric acid:
BrF3 is a fluorinating agent, but less reactive than ClF3. The liquid is conducting, owing to autoionisation:
Many ionic fluorides dissolve readily in BrF3 forming fluoroanions:
Covalent fluorides may also react as fluoride acceptor, which make them acidic in this solvent: