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Phase diagram of the system AlF3-RbF was investigated by the methods of DTA, DSC and XRD with quenching technique. Three compounds were identified: Rb3AlF6; RbAlF4 and RbF·3AlF3. Rb3AlF6 melts congruently at 878°C and α ⇋ β transforms reversibly at 340°C. Eutectic E1 between Rb3AlF6 and RbF is located in 10.0 mol% AlF3 at 729°C. RbF·3AlF3 melts incongruently at 745°C, reacting with Rb3AlF6, second eutectic E2 was observed in 48.4 mol% AlF3 at 486°C. The third compound RbAlF4 was formed in the solid eutectic when it cooled below 473°C. A very small thermal effect corresponding to α ⇋ β transformation at 335°C was observed on the DTA curve of this compound. All phase structures in the system were confirmed by X-ray powder diffraction analysis.

The systems RbF–GaF3 and CsF–GaF3 were re-investigated by DTA and XRD method. In the system RbF–GaF3, with eutectic E1 at 750°C in the location of 8.5 mol% GaF3 and E2 at 749°C in the location of 43.0 mol% GaF3, three compounds Rb3GaF6, RbGaF4 and RbF·2GaF3 were identified and indexed by XRD. The indexed result of α-Rb3GaF6 could not be successfully obtained, β-Rb3GaF6 is tetragonal, a=6.324±0.004, c=8.860±0.003 A. RbGaF4 is orthorhombic, a=9.821±0.006, b=9.517±0.005, c=8.060±0.006 A; RbF·2GaF3 is also orthorhombic, a=9.459±0.005, b=9.336±0.005, c=7.685±0.005 A. In the system CsF–GaF3, with eutectic E1 at 664°C in the location of 7.5 mol% GaF3 and E2 at 675°C in the position of 44.0 mol% GaF3, two compounds were confirmed. α-Cs3GaF6 is orthorhombic with a=10.62±0.02, b=9.959±0.006 and c=5.607±0.005 A; β-Cs3GaF6 is also orthorhombic, a=10.356±0.003, b=8.280±0.003, c=7.621±0.005 A; γ-Cs3GaF6 is tetragonal, a=6.833±0.003, c=9.869±0.002 A; CsGaF4 is orthorhombic, a=8.571±0.007, b=7.575±0.007 and c=6.981±0.006 A.

The phase diagram of the KF–InF3 system was investigated by DTA and XRD methods. In the system, two incongruent compounds, 2KF·InF3 and KInF4, were observed. The compound 2KF·InF3 was XRD-indexed as orthorhombic, where a=8.870±0.003, b=6.271±0.002, c=4.553±0.001 A. Another compound KInF4 polymorphously reacted at 784 °C. The room temperature phase was tetragonal, where a=7.160±0.004 and c=5.068±0.007 A. The structure of higher temperature phase has not been determined yet. An eutectic point was observed at 785 °C at 19.0 mol% InF3.