Tetraphenylphosphonium and especially tetraphenylarsonium salts were formerly of interest in gravimetric analysis of perchlorate and related oxyanions.

The rigidity of the phenyl groups facilitates packing and elevates the melting point relative to alkyl-based quaternary ammonium salts.

Also, since these salts are soluble in organic media, a wide range of solvents can be employed for their crystallisation.

2751-90-8), which in turn was synthesized by passing dry oxygen through the reaction of phenylmagnesium bromide and triphenylphosphine.

Tetraphenylphosphonium salts of inorganic or organometallic anions are often sought because they are easily crystallized.