Thermodynamic parameters of thorium-fluoride complexes from measurements with the fluoride-selective electrode at 5, 25, and 45°C

Abstract

Stability quotients for the thorium-fluoride and hydrogen-fluoride systems in 0·01 M NH 4NO 3 at 5, 25, and 45°C were determined from measurements of free fluoride ion concentration by the lanthanum fluoride membrane electrode. Thermodynamic stability constants, standard enthalpies, and standard entropies were derived from the experimental data for formation of ThF 3+, ThF 2 2+, ThF 3 +, ThF 4, and HF.