Polarographic studies in molten LiNO3 NaNO3+ KNO3. Part 2.—Stability constants of halide complexes

Abstract

The stability constants of the chloro- and bromo-complexes of Ni^II, Co^II, Cd^II, and Pb^II have been determined in the LiNO₃3+NaNO₃+KNO₃ eutectic solvent at 145°C. Some preliminary experiments have also been carried out in melts containing fluoride and cyanide ions. The experimental data were analyzed by a Ferranti 1900 series computer. This procedure led to difficulties in some cases and graphical methods were then employed. The order of stability of the complexes was : Cl(Ni^II)< Br(Ni^II)∼Cl(Pb^II)< Br(Pb^II)< Cl(Cd^II)< Br(Cd^II). For each metal ion, the order of stability was : {F(M^II)} Cl(M^II)< Br(M^II){CN(M^II)} Structural changes, leading to long-lived species, may occur in the Co^II-halide systems.