A series of triphenylphosphine stabilized platinum dialkyl compounds of the type (Ph2P)3PtR2where R = methyl, ethyl, ethyl-d3,n-propyl,n-butyl, andn-hexyl have been synthesized and their infrared spectra in the CH stretching region have been obtained. These spectra are discussed in terms of the infrared spectra of hydrocarbons which are chemisorbed on transition metal catalysts.