The mutual effect of atomic groups in acid chlorides of threeand four-coordination phosphorus was investigated by the nuclear quadrupole resonance of Cl35 (NQR Cl35) and Raman spectroscopy methods. On the basis of the NQR data it is suggested that in the ground state the interaction of unshared pairs of chlorine with the d orbitals of phosphorus is displayed weakly and the interaction of the indicated atoms is accomplished predominantly by an inductive mechanism. The integral intensities of the Raman lines of vibrations of the P-Cl and P=Cl bonds were measured. The Raman scattering data and the results of quantummechanical calculations by the molecular orbital method indicate some additional multiplicity of the P-Cl bond.