The raman spectra of some metallic halides
The paper describes the results of the study of the Raman spectra of the halides of cadmium and zinc as well as of magnesium chloride, magnesium bromide and aluminium chloride. All the halides of cadmium and the chloride and bromide of zinc have yielded lines wich show the existence of homopolar binding in them. The spectra of zinc chloride and cadmium iodide were fairly intense in contrast to the weak and doubtful lines obtained by the previous investigators, and indicate a linear triatomic model for them analogous to those of mercuric halides.
Marked differences in intensity, sharpness and frequency have been observed in zinc chloride, cadmium bromide and cadmium iodide from crystal to solution and with different solvents. The presence of halogenions in solution also affect the characteristics of the spectra considerably. These are explained partly by the change in the degree of ionisation in different solvents and partly by the influence of the solvent molecule on the fundamental oscillation frequencies of these compounds. It has been pointed out that the Raman effect data obtained for the cadmium halides do not furnish sufficient evidence for the formation of complex ions of the type CdX4″ in solution.
Magnesium chloride, magnesium bromide and aluminium chloride gave on Raman lines. A pronounced effect on the bands of water was noticed in each case.