On the analogy between the restricted primitive model and capacitor circuits. Part II: A generalized Gibbs-Duhem consistent extension of the Pitzer-Debye-Hückel term with corrections for low and variable relative permittivity

We present a novel, thermodynamically consistent modification of the Pitzer-Debye-Hückel term and its extension for concentration dependent density, molar mass relative permittivity. This is validated ionic liquids by comparison with reference model from literature and, in contrast to similar extensions, also applied conventional salts small spherical ions aqueous, mixed non-aqueous solvents. The central novelty inclusion modified parameter closest approach, which improves overall qualitative performance over complete permittivity range. Gibbs-Duhem consistency retained sample calculations aqueous [BMIM][BF4] NaCl are provided. extended properties combined predictive COSMO-RS-ES calculation phase equilibria activity coefficients electrolytes salts. predictions salt solubility fully media significantly upon introduction within long-range electrostatics. Modelling outperforms modelling unmodified extensed as well term. correlated mixture overestimated respect experimental values kinetic depolarization effects provide plausible explanation this observation. Overall, our results support electrostatic theory order improve particular emphasis on electrolytes.