Vapor Pressure and Molecular Composition of Vapors of the RbF–ZrF 4 and LiF–ZrF 4 Systems

S> The vapor pressures of RbF and LiF were measured over the temperature intervals 589-1059 and 8511060 , respectively. Thermal analysis showed the melting poiat of RbF to be 798 . Vapor pressures of the RbF- ZrF/sub 4/ and LiF-ZrF/sub 4/ systems were measured over the ranges 690-1060 and 670- 1060 , respectively. On the basis of previously developed theory, it was concluded that the complexes RbZr/sub 2/F/sub 9/ and LiZr/sub 2/F/sub 4/ exist in the vapor phase of the respective systems. Farther work on the NaF-ZrF/sub 4/ system points to the existence of the gaseous complex NaZr/sub 2/F/sub 9/ rather than NaZrF/sub 5/ as previously supposed. A phase diagram of the RbF-ZrF/sub 4/ system derived from vapor pressure data shows a constant boiling point to exist at about 33 mole% ZrF/sub 4/ for a total pressure of 1 mm. Plots showing the change of totai pressure with composition for various temperatures, as well as melting point curves, are given for the various systems.