Complex formation in molten salts. Part 2.—Association constants of silver chloro-complexes in molten eutectic NaNO3+ Ba(NO3)2

Abstract

E.m.f. measurements in dilute solutions of Ag⁺ and Cl^– in molten eutectic NaNO₃+ Ba(NO₃)₂(94.2:5.8 mol %) at 350, 375 and 400°C have been used to evaluate thermodynamic association constants K₁₁ and K₁₂ for the formation of the species AgCl and AgCl^–₂. Results did not suggest the formation of Ag₂Cl⁺. Temperature-coefficients of association constants were, within limits of experimental precision, predictable from calculations based on the quasi-lattice model. The specific bond free energy for the formation of AgCl in this melt has been compared with the values reported in other nitrate melts. It is found that the reciprocal coulomb effect is inadequate in predicting the magnitude or the direction of stabilization of the AgCl bond in molten NaNO₃+ Ba(NO₃)₂ eutectic relative to that in molten NaNO₃.