Non-ideal behaviour of the sulphates in aqueous ternary solutions. Excess thermodynamic functions

Determination of the mean activity coefficients in ternary systems of the type sulphate I+ sulphate II-H2O (where I=Cu,Zn, II=Li, Na, Mg, Mn) the existance of strong deviations from the ideal behaviour. Estimation of thermodynamic excess functions from the variation of the mean activity coefficients with temperature draws lip to the conclusion that the high values obtained are due the formation of the ionic associates, process that rakes place with important mixing effects and in which the hydration sphere of the single ions is partially destroyed, these meaning a modification of the number of liberty degrees.