Thermodynamic Characteristics of Samarium and Europium Chlorides in Molten Alkali Metal Chlorides

Abstract

The formal standard redox potentials of samarium (III)/(II) (E*Sm3+/Sm2+) and europium (III)/(II) (E*Eu3+/Eu2+) in molten alkali metal chlorides were measured potentiometrically against a reference chlorine electrode. The Gibbs energy changes and equilibrium constants for the reaction LnCl2(1) + 1/2 Cl2(g) ⇔ LnCl3(1) were calculated for the salt systems studied. The effect of the cationic composition of the melt-solvent on the above thermodynamic characteristics is also reported.