Quantum chemical calculations (MP2 and B3LYP methods) and vibrational analysis were performed on the compounds that contain carbon–phosphorus multiple and single bonds: HCP, FCP, ClCP, CH 3CP, (CH 3) 3CCP, CH 2PCl, CF 2PH, CF 2PCF 3, CH 3PCl 2, CF 3PH 2 and their deuterated species. The calculations gave vibrational wavenumbers in good agreement with the observed wavenumbers. The stretching modes of the carbon–phosphorus bonds are apt to couple with other modes, giving relevant infrared and Raman bands in extensive wavenumber ranges. The intrinsic CP, CP and C–P stretching wavenumbers are estimated to be around 1250, 980 and 700 cm −1, respectively. The calculated values (B3LYP method) of the stretching force constants for the CP and CP bonds, 915–987 and 512–598 N m −1, are roughly three and two times, respectively, the values for the single bond, 266–284 N m −1. The relationship between the stretching force constants f (N m −1) and the bond lengths r (10 −10 m) for the carbon–phosphorus multiple and single bonds is represented by f=2.9×10 2/( r−0.87) 3.