The Cl-O bond in chlorine oxides: Electronic structure and empirical force constants

The nature of the Cl-O chemical bond is investigated in a series of chlorine oxides. Several parameters, both experimental and theoretical, are used for this purpose. The geometrical structure is taken from the literature. Force constants are derived from experimental frequencies for 11 molecules, where data from isotopic species, up to a number of 52, are used. Also a topological study of the B3LYP/6-311+G(2d) electron density is carried out. All the parameters mentioned are related and discussed to analyse the different kinds of Cl-O bonds, and a classification is put forward, in which three different types of Cl-O bonds are found.