Structure of molten systems KF?K2TiF6 and KCL-K2TiF6

Congruently melting compounds K₃TiF₇ and K₃TiF₆Cl which are formed in the systems KF? K₂TiF₆ and KCl? K₂TiF₆, respectively, exhibit a strong influence on the structure (ionic composition) of the melts of the corresponding systems. Considering the relatively low symmetry and a high energetic state of the TiF₇^3? and TiF₆Cl^3? complex ions, a high degree of their thermal dissociation might be expected. This assumption was confirmed by two different methods based on a thermodynamic analysis of the phase equilibria and of the volume properties of the investigated systems, respectively. In connection with the former method, the values of the enthalpy of fusion of K₂TiF₆, K₃TiF₇, and K₃TiF₆Cl which were used in the calculations have also been estimated.