Molar volumes and refractivities of highly concentrated solutions of ammonium and potassium thiocyanates in water and dimethylsulphoxide

Abstract

Densities and refractive indices of highly concentrated solutions of ammonium and potassium thiocyanates in water and dimethylsulphoxide have been measured at 333.2 K in the composition range from xs = 0.01 up to saturated solutions. Molar volumes and apparent molar volumes have been calculated from density measurements and their concentration dependences are discussed. All the systems are volumetrically non-ideal and exhibit negative deviations from additivity. The molar refractivities were calculated from the refractive indices using the Lorentz–Lorenz equation. The refractivity values of individual ions were estimated in infinitely dilute solutions and were used for discussion of ion–solvent interactions.