Vibrational spectrum of chlorine heptoxide

摘要

The infrared and Raman spectra of chlorine heptoxide, Cl2O7, have been recorded in the vapor, liquid, and solid phases. The fundamental vibrations, with the exception of the two torsional modes, have been assigned underC2symmetry. The resulting assignment leads to a near degeneracy of the skeletal stretches near 700 cmminus;1, and places the skeletal bending mode at 154 cmminus;1. A normal coordinate analysis has been carried out for Cl2O7and related ClO3grouphyphen;containing molecules. Similarities in the skeletal stretching force constantslpar;KRsime; 3thinsp;mdynsol;thinsp;Aring;rpar;and in theClsngbnd;Obond lengths of Cl2O and Cl2O7suggest that bonding is substantially the same in both molecules, thus implying aClsngbnd;Osingle bond in the skeleton of Cl2O7. Thermodynamic properties of Cl2O7have been calculated using torsional frequencies estimated from mean amplitudes of vibration.