ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Thermodynamic Calculation of Phase Diagrams  of Systems in which One Component Undergoes Thermal Dissociation

V. Daněk and I. Proks

Institute of Inorganic Chemistry, Slovak Academy of Sciences, SK-842 36 Bratislava

Abstract: Thermodynamically consistent calculation of the phase diagram of systems, in which one component thermally dissociates, is proposed. For the calculation of the activity of the component, undergoing thermal dissociation, the standard state of the dissociated pure compound was chosen. The expressions for the activity of components were derived.The proposed thermodynamic approach was verified by calculation of the phase diagram of the systems MF-M₂SO₄ (M = Na, K), where the congruently melting compounds M₃FSO₄ are formed. It was found that the degrees of thermal dissociation of these compounds, calculated in the proposed way, attain the values α_*(Na₃FSO₄) = 0.71 and α_*(K₃FSO₄) = 0.76, which are the same values as obtained by means of conventional methods.

Full paper in Portable Document Format: 481a7.pdf

Chemical Papers 48 (1) 7–10 (1994)