Density of the system LiF-KF-K2NbF7

The density of the melts in the system LiF-KF-K2NbF7 has been measured usin g the Archimedean method. On the basis of the determined density values the molar volume, partial molar volume, and excess molar volume of the melts w ere calculated. In the boundary system KF-K2NbF7 the congruently melting co mpound K3NbF8 is formed. This compound exhibits a low thermal stability and at melting it undergoes a thermal dissociation. The degree of the thermal dissociation was calculated on the basis of both the thermal analysis of th e phase diagram and the volume properties of the investigated system. It wa s found that the degree of the thermal dissociation of K3NbF8 at the meltin g point attains the value alpha (0) = 0.44.