Matrix-isolation and mass spectrometric studies on the vaporisation of chromium(III) bromide: characterisation of molecular CrBr4, CrBr3 and CrBr2

Abstract

Mass spectrometric and matrix-isolation IR studies on the vaporisation of solid chromium(III) bromide indicated the presence in the vapour of three different chromium halide species, together with molecular bromine. In the initial stages of heating the most volatile chromium species is CrBr₄, but at progressively higher temperatures molecular CrBr₃ and subsequently CrBr₂ are produced. The chromium and bromine isotope structure has been resolved for these latter species, and their IR spectra have been shown to be consistent with planar (D_3h) and linear geometries respectively.