STRUCTURE OF THE MELTS OF THE SYSTEM KF-K2MOO4

The densities of the melts in the system KF-K2MoO4 were measured using the Archimedean method. From the volume properties point of view the investigated system exhibits almost ideal behaviour, which indicates that the congruently melting compound K3FMoO4 which is formed in the system KF-K2MoO4 exhibits a low thermal stability and at melting it undergoes a considerable thermal dissociation. The degree of the thermal dissociation was calculated on the basis of both the thermodynamic analysis of the phase diagram and the volume properties of the investigated system. It was found that the degree of thermal dissociation of K3FMoO4 at the melting point attains the value alpha0 = 0.81. The dissociation enthalpy, calculated on the basis of the density-values, is DELTAH(dis, K3FMo04) = 18.8 kJ mol-1.