Determination of thulium valent state in mixture of molten chlorides KCl-LiCl-TmCl2 being in equilibrium with metallic thulium

Using the method of measuring EMF investigated are equilibriums of thulium ions of different oxidation degree with metallic thulium in equimolar mixture of K and Li molten chlorides. EMF of galvanic elements is measured in the temperature range of 573-923 K when thulium chloride content in an electrolyte is 0.45-4.06 mass%. Calculations are made for the determination of a part of different valence ions being in electrolyte and for apparent standard electrode potentials and equilibrium constants of Tm3+Tm0 reversible Tm1+, Tm2++Tm0 reversible Tm1+ reactions. It is shown that in a melt of KCl-LiCl-TmCl3 salts at the temperatures investigated ions of lower oxidation degrees are in equilibrium with thulium