Thermodynamic equilibrium between melt and crystalline phase of a compoundA(q)B(r) with dystectic melting point IV. Application to the systems NaF-NaMgF3 and KF-KMgF3

The LeChatelier-Shreder equation describing the equilibrium between crystal line phase and melt in the system A-AB when substance AB partially dissocia tes upon melting was applied in the systems NaF-NaMgF3 and KF-KMgF3. The di ssociation enthalpy, the heat of fusion at dystectic temperature of fusion, and the degree of dissociation of compounds NaMgF3 and KMgF3, formed in th e melt, were calculated without using any fictive quantity. The dissociatio n degrees of NaMgF3 and KMgF3 have been found to be alpha (+) (NaMgF3) = 0. 23 and alpha (+) (KMgF3) = 0.11, respectively.