The Infrared Spectra of Metal Dialkylphosphorodithioates

The infrared spectra of eight zinc dialkylphosphorodithioates and four potassium dialkylphosphorodithioates have been examined The infrared spectra of the zinc, cadmium, copper, nickel, and potassium salts of a mixed dialkylphosphorodithioate have been studied and compared to the spectrum of the parent acid. The P-O-C absorption of all of these compounds is found to occur about 25 cm −1 lower in frequency than in compounds containing the P = 0 group. The thiophosphoryl group (P = S) is found to occur at 635–668 cm −1 both for the free acid and the covalent salts. It occurs at a higher frequency, 675–702 cm −1 for the more ionic potassium salt. The P— S—(M) absorption occurs at 510–556 cm −1 .