Electrode Potentials of Thorium Tetrachloride in Alkali Chloride Melts

The electrode potentials of the system Th, ThCl4 (KCl, NaCl) were measured at various concentrations of thorium chloride, and at temperatures between 670 °C and 850 °C, using a silver – silver chloride reference electrode. It was shown by a direct gravimetric method that the reaction,Th(metal) + ThCl4(melt) = 2ThCl2(in melt),postulated by previous investigators, did not take place.The activity coefficients, and the other partial molal properties of the solutions of ThCl4, in the equimolar mixture of potassium and sodium chlorides, were calculated as a function of temperature from the e.m.f. measurements.