Infra-red and Raman spectra of dimeric gallium trihalides

Abstract

The infra-red spectra of dimeric gallium trichloride, tribromide and tri-iodide have been recorded in the range 50–800 cm^–1. These results, in conjunction with the Raman spectra and polarzation measurements on the trichloride and tribromide, are consistent with a bridged (D_2h) dimeric molecular unit in the solid and liquid phases, and the spectra have been analyzed accordingly; analogies with these spectra make possible a partial assignment of the infra-red-active fundamentals of gallium tri-iodide.