Thermodynamic equilibrium between melt and crystalline phase of a compoundA(q)B(r) with dystectic melting point I. Theoretical approach

To describe the equilibrium between the crystalline phase and melt in the s ystem A-A(q)B(r), when the substance A(q)B(r) partially dissociates upon me lting, the special form of the LeChatelier-Shreder equation was derived wit hout assuming any hypothetical equilibrium states and the occurrence of any hypothetical thermodynamic quantities. To fit both the phase and the chemi cal equilibrium in the system A-A(q)B(r), an original method for the calcul ation of the values of the degree of dissociation of the compound A(q)B(r) in the melt, the heat of fusion at dystectic temperature of fusion, and the dissociation enthalpy using this equation was proposed.