PITZER PARAMETERS FOR THALLIUM(I) CHLORIDE IN AQUEOUS-SOLUTIONS AT 298.15 K FROM SOLUBILITY MEASUREMENTS IN TLCL-LICL-H2O AND TLCL-KCL-H2O SYSTEMS

The solubility of thallium(I) chloride has been measured in aqueous so lutions of lithium chloride and potassium chloride at concentrations r anging from 0.005 to 4.0 mol kg-1 at 298.15 K. The data were analysed using Pitzer's virial coefficient treatment without explicit assumptio n of association to ion pairs. Single electrolyte parameters for TlCl, beta(0) and beta(1) were evaluated assuming C(phi) = 0. Although alph a = 2 gave a satisfactory fit of the experimental data, as it does for a wide variety of electrolytes, the best fit of the experimental data was obtained with alpha = 7. However, when the results were combined with those for previous systems, it was found that alpha = 2 gave more consistent values for Pitzer's parameters as well as the thermodynami c solubility product of thallium(I) chloride. Mixture parameters relev ant to a particular mixture, theta and psi, were also evaluated.