Determination of the thermodynamic parameters of hexaoxoiodate(VII) hydrates of the type M 2HIO 6· nH 2O, where M II = Ni, Cu, Zn and Cd, by solubility measurements in water at various temperatures

Abstract

The solubilities of metal hexaoxoiodate(VII) hydrates of the type M 2HIO 2 · nH 2O (M II = Ni, Cu, Zn, Cd; n = 3, 2, 1.25, 1.25) in water have been measured at several temperatures with the aid of 4-(2'-thiazolylazo)-resorcinol (TAR) reagent using a Beckman DU-2 spectrophotometer. Mean activity coefficients are determined. The thermodynamic parameters of these salts, e.g., Δ H o, Δ G o and Δ S o, have been computed. A retrograde solubility phenomenon has been observed over the temperature range 298.5–328 K.