The vibrational spectra of the halides and complex halides of the Group IIB elements. Part II. A Raman spectroscopic study of the systems HgX2–LiX (X = Cl, Br) in aqueous and tri-n-butyl phosphate solutions

Abstract

The Raman spectra of aqueous solutions containing varying proportions of mercuric halide and lithium halide, and of the tri-n-butyl phosphate (TBP) extracts of these aqueous solutions are reported. Although the HgX₃^– anion is not observed in aqueous solution, it seems to be the most stable species in the tri-n-butyl phosphate extracts. The extraction of mercury(II) from aqueous lithium halide solutions into tri-n-butyl phosphate thus differs from the previously reported extraction from concentrated halogen acids. Expressions are derived for the distribution ratio of mercury(II) for the individual extraction of HgX₄^2– and HgX₃^–, and the dependence of the distribution ratios on the lithium ion, halide ion, and tri-n-butyl phosphate concentrations is verified experimentally.