Perfluorophenyl derivatives of the elements

The relatively stable white solid tris(pentafluorophenyl)boron has been prepared in high yield from boron trichloride and pentafluorophenyllithium using pentane as a solvent. It shows strong acceptor properties towards the Lewis bases: ammonia, trimethylamine, triphenylphosphine, and pyridine. With excess of pentafluorophenyllithium the salt lithium tetrakis(pentafluorophenyl)borate is formed; the water-soluble borate precipitates the tetraethylammonium and potassium derivatives from concentrated aqueous solutions.