Abstract

Phosphorus forms many fluorine compounds, including the binary fluorides, oxyfluorides, thiofluoride, and the various fluorophosphoric acids and their salts. Whereas PF₅ behaves as a Lewis acid, phosphorus trifluoride behaves as a Lewis base. PF₅ is used as a catalyst in the electronics industry and in ion implantation for semiconductors. The mono-, di-, and hexafluorophosphoric acids are commercially available. Hexafluorophosphoric acid is used in polymerization and preparation of its salts, a number of which exist. Particularly important commercially are sodium monofluorophosphate and potassium hexafluorophosphate, used as a dentifrice additive and as a catalyst for polymerization processes, respectively. The highly toxic fluorophosphate esters have found use in medical applications as well as in warfare. The polymerized esters are also known.