Enthalpies of solution and dilution of aqueous solutions of sodium diclofenac salt were measured by isoperibolic calorimeter
at 293.15, 298.15, 303.15, 308.15 and 318.15 K. The concentration of the electrolyte was restricted to solubility salt at
various temperatures and did not exceed 0.035–0.057 mol kg−1 values depending on the studied temperature. The virial coefficients were derived from Pitzer’s model and the excess thermodynamic
functions of both the solution and the components of the solution were calculated. The analysis of thermodynamic characteristics
of the solution from concentration and temperatures was carried out and discussed.