Spectral and structural studies of some Group VIA dioxydihalides

Abstract

The infrared and mass spectra of MoO2Cl2, MoO2Br2, WO2Cl2, and WO2Br2 in the gas phase have been studied. The vapours contain mostly monomeric molecules but there is also a small amount of relatively unstable dimeric species present in each case. In inert solvents MoO2Cl2 and MoO2Br2 are dimeric and the infrared spectra are reported. In the solid state all four compounds are polymeric and the absence of the characteristic M = O infrared frequency suggests that only bridging oxygen atoms can be present. X-ray powder diffraction data suggest that the four compounds are isomorphous.