Thermodynamic properties of CuSO₄(aq) from 268 K to 377 K and phase equilibria in the CuSO₄–H₂O system

This paper reports a comprehensive thermodynamic treatment of the binary system CuSO₄–H₂O including solution properties and various phase equilibria. Published thermodynamic data of CuSO₄(aq), solubilities of the hydrates of copper sulfate, and equilibrium data of the hydration-dehydration reactions have been collected and critically assessed. Using an internally consistent database of solution properties in the temperature range (268–377) K, the parameters of an interaction (Pitzer) model were determined. With this model activity coefficients and water activities of saturated CuSO₄ solutions have been calculated yielding, together with equilibrium data of hydration–dehydration reactions, the thermodynamic solubility products of CuSO₄·5H₂O, CuSO₄·3H₂O, and CuSO₄·H₂O. The complete phase diagram of the system CuSO₄–H₂O has been established. Graphical abstract: .