Ion Polarizabilities in Binary Liquid Mixtures of Water/Organic Solvents.

Using our recently proposed method to obtain salt and ion polarizabilities in aqueous solutions, we determine the polarizabilities of five salts (LiCl, NaCl, NaBr, KBr, and MgSO4) in water-acetonitrile, water-ethanol, and water-acetone solutions at eight different water-organic solvent compositions at the D-line of sodium (589.3 ± 0.1 nm). Setting Li+ as the reference ion, we determine the ion polarizabilities of Na+, Cl-, and Br- in binary liquid mixtures. Our results show that cation polarizability is nearly unaffected by solvent composition, but anion polarizability exhibits a nonmonotonic behavior with increasing mole fraction of the organic component in the liquid mixture. This suggests that ion polarizability in a solution is affected by the solvent. The results of salt and ion polarizabilities can be used as important reference data for physical chemistry, atmospheric science, and biophysics.