Phosphorus Trifluorodibromide, PF₃Br₂

Phosphorus Trifluorodibromide, PF₃Br₂, was first produced by passing bromine into phosphorus trifluoride cooled by a freezing mixture. It is a pale brown fuming liquid which freezes to a yellow solid at -20° C. and decomposes at ordinary temperatures in a similar manner to the dichloride:—

5PF₃Br₂ = 3PF₅ + 2PBr₅

On complete hydrolysis it gives H₃PO₄, HF and HBr.

The corresponding diiodide, PF₃I₂, is probably formed when the trifluoride is absorbed by iodine. It is a yellowish-red solid.