A survey study of the vibrational spectra of some aquo-halogenocomplexes

Abstract

I.r. (and a few Raman) spectra are reporeted for the series M₂^I[MX₅(H₂O)], M₂^I[MX₄(H₂O)₂], MX₂,2H₂O, and MX₂,6H₂O. From shifts in frequency with change of cation, metal, and halogen (X) the wagging mode of coordinated water is assigned at higher frequency than the rocking mode, contrary to currently accepted wisdom. Use of deuteriation has enabled identification of ν(Mâ†�OH₂) and δ(M–O) modes in many cases. It is suggested that CoBr₂,6H₂O has the structure [CoBr₂(H₂O)₄],2H₂O and does not contain the hexa-aquo ion.