Collect. Czech. Chem. Commun. 1987, 52, 1680-1691

The principle of ionic additivity and interaction parameters for the systems water-salt

Ivan Horsák and Ivo Sláma

Institute of Inorganic Chemistry, Czechoslovak Academy of Sciences, 160 00 Prague 6


A theoretical approach to the evaluation of water-salt phase diagrams has been developed which leads to the concentration dependence of the activity coefficient of water. Literature data for water-alkali halide systems were used to evaluate these dependences in an empirical manner and by using an equation derived from the lattice model of electrolytes. As an alternative, a joint evaluation of all the data was made by invoking the applicability of the principle of ionic additivity to the interaction parameters. In this way, an economical prototype of a data bank of interaction parameters of electrolyte systems has been established. The approach adopted represents a significant step forward in the generalization and prediction of solid-liquid phase equilibria in the systems water-salt.