A synthetic route to ethynylphosphonium salts from haloacetylenes, phenylhaloacetylenes, but not alkylhaloacetylenes is described. These salts are electrophiles; when phenylethynyltriphenylphosphonium bromide is treated with tributylphosphine in acetonitrile, the a, p-bis (tributy1phosphonium) styrene dibromide is formed. Rate data for the second- order reactions of several systems in DMF are (AH*, kcal/mol; AS*, eu; k, M-'sec-'at 36”): ...