  Differential thermal analysis up to complete melting was performed for the
complete pseudobinary system LiF-BiF3. Melts with high bismuth fluoride
concentration show severe evaporation, nevertheless even pure BiF3 could be
molten at 655 deg. C. The system contains one intermediate compound BiLiF4
which melts by peritectic decomposition under the formation of LiF at 415 deg.
C. The eutectic between BiLiF4 and BiF3 melts at 415 deg. C. By thermodynamic
assessment the following parameters were found for BiLiF4: \Delta H=-1514900
J/mol, S=158.5 J/mol K, c_p=166.173 -0.01072 T (in J/mol K). The melt has
negative excess Gibbs free energy.
