Pitzer’s formulation

Pitzer s formulation offers a satisfactory and desirable way to model strong electrolyte activity coefficients in concentrated and complex mixtures. When sufficient experimental data are available, one can make calculations which are considerably more accurate than those presented in this paper. Attaining high accuracy requires not only experimentally-based parameters but also that one employ third virial coefficients and additional mixing terms and include explicit temperature dependencies for the various parameters. 

Pitzer s formulation allows the calculation of the thermodynamic properties of concentrated aqueous solutions, up to solubility limits (e.g., Harvie et al. 1984). 

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