The influence of solvent nature on thermodynamic properties of the reaction Tm(III)+e¯⇔Tm(II) in molten chlorides

► Thulium chloride compounds as fission products. ► The investigation of electrochemical properties of thulium ions in molten chlorides. ► Determination of the apparent standard redox potentials of the couple Tm3+/Tm2+ in fused NaCl-KCl and NaCl-2CsCl salts. ► The influence of the nature of solvents on thermodynamic properties of thulium (III) is discussed.