CONFORMATIONAL AND BOND PROPERTIES OF CHLOROSULFONYL ISOCYANATE, CLSO2NCO

The Raman and IR spectra of chlorosulfonyl isocyanate in the liquid phase are reinvestigated, and the IR spectra of the vapour phase are recorded. A complete assignment of the observed bands is proposed. Subsequently a normal coordinate analysis is performed. Vibrational data confirm that ClSO2NCO exists only in one single conformation in both phases. The presence of depolarized bands in the Raman spectra of the liquid phase is consistent with either C-1 symmetry and a very low rotational barrier between the two equivalent optic isomers or with a C-s symmetry. This interpretation allows the rationalization of data obtained from several spectroscopic techniques. An unusual force constant-bond length relationship is found for the S-Cl moiely.