Thermodynamics of electrolyte mixtures. Activity and osmotic coefficients consistent with the higher-order limiting law for symmetrical mixing

The parameters for symmetrical mixing of ions of the same sign in the virial-coefficient (Pitzer) system are evaluated from literature data for 25°C in a manner consistent with the higher-order limiting law of Friedman. Twenty-four systems involve cation mixing with a common anion and fourteen involve anion mixing with a common cation. Heat of mixing data were similarly treated in a recent publication; the results give the temperature coefficients of some of these same parameters. The combined results yield the mixing parameters as functions of temperature on a basis both self-consistent and in accord with the limiting law. The results also yield, for a few systems without a common ion, predicted values in good agreement with experimental data.on leave from Liaoning University, Shenyang, China.     

Activity coefficients in aqueous NaCl−CsCl2 mixtures from solubility data up to 75°C: A supplement to Pitzer's work

Activity coefficients of NaCl in aqueous NaCl-CsCl₂ mixtures in the CaCl₂ rich region at 25, 50 and 75°C were calculated from recent solubility data of Chou and his group. The results are compared with those obtained from ion-interaction equations using solution data of de Lima and Pitzer, who had also reported similar comparisons but using the inconsistent solubility data of Plyushchev et al. The agreement obtained between the Chou solubility data and the Pitzer equation is excellent.