Tetraphenylphosphonium chloride

Tetraphenylphosphonium chloride is the chemical compound with the formula [(C₆H₅)₄P]Cl, abbreviated Ph₄PCl or PPh₄Cl or [PPh₄]Cl, where Ph stands for phenyl. Tetraphenylphosphonium and especially tetraphenylarsonium salts were formerly of interest in gravimetric analysis of perchlorate and related oxyanions. This colourless salt is used to generate lipophilic salts from inorganic and organometallic anions. Thus, [Ph₄P] is useful as a phase-transfer catalyst, again because it allows inorganic anions to dissolve in organic solvents.