NaI-RbI equilibrium phase diagram. Phases at equilibrium for the chemical system NaI-RbI are shown as a function of chemical composition (mole percent RbI) and temperature at atmospheric pressure (1 bar). This Iodide system is similar to the alkali feldspars in that there is partial solid solution between the NaI and RbI phases. The melting temperature for each of the solids depends on its chemical composition, and the composition of the melt formed depends on the chemical composition of the solid melting. At lower temperatures there is a two-phase region bounded by a solvus. A mixture of those two phases melts at a eutectic. This diagram is based on the collection of alkali halide phase diagrams by Sangster and Pelton (1987).
Mole % RbI:
Temperature:
