AbstractThe kinetics of oxidation of triphenyl derivatives of group V elements Ph3M (M = P, As, Sb) by potassium peroxodisulfate have been investigated spectrophotometrically in 60% acetonitrile–40% water (v/v) mixture. The reaction follows second‐order kinetics, first order in each reactant. Changes in the [H+] and ionic strength have negligible effect on the reaction rate. Addition of acrylonitrile fails to inhibit the rate. The results indicate a rate‐determining nucleophilic displacement of the Ph3M molecule on the peroxide linkage. The relative rate order has been found to be Ph3P>Ph3Sb>Ph3As. This can be attributed to two conflicting t