Chlorine Tetraoxide

摘要

The existence of the ClO_4 radical, one of the simplest chlorine oxides ClO_x (x =1 - 4), has not vet been unequivocally established. Yet it has been postulated as a reactive intermediate in several reactions and should be a binary compound of fundamental significance. ClO_4 is probabh an intermediate in the photochemical formation of Cl_2O- from Cl_2 and O_3. as well as in the thermal decomposition of Cl_2O_6 and Cl_2O_7, and in the anodic oxidation of ClO_4~- ions. An indication of the existence ofClO_4 was obtained from ESR measurements on KClO_4 crystals that had been irradiated with X-rays. However, the assignment and analysis of the ESR signals is still controversial. The formation enthalpy of the endothermic ClO_4, derived from mass spectrometric and kinetic measurements on Cl_2O, amounts to 200 270 kJ mol~(-1).