STUDIES OF LITHIUM HYDRIDE SYSTEMS. III. SOLID-LIQUID EQUILIBRIUM IN THE LITHIUM BROMIDE-LITHIUM HYDRIDE AND LITHIUM IODIDE-LITHIUM HYDRIDE SYSTEMS

Thermal analysis has been used to determine the temperature—composition solid—liquid equilibrium diagrams for the two binary systems, LiBr–LiH and LiI–LiH. Both are simple eutectic systems with no experimental evidence for the formation of solid solutions. Eutectic compositions of 29.7 mole % lithium hydride, mp 453.3°C, and 23.5 mole % lithium hydride, mp 390.8°C, were observed for the bromide and iodide systems, respectively. The values of the chemical potential of each component have been calculated along the equilibrium curves where the solutions are saturated with respect to the pure solids.The limiting slopes of the saturation curves are consistent with the interpretation that lithium bromide and lithium iodide both exist primarily as un‐ionized dimers when dissolved in lithium hydride and that lithium hydride exists primarily as an un‐ionized monomer when dissolved in either lithium halide.