Thermochemical study of the liquid systems BaO-B2O3 and CaO-B2O3

Abstract

The integral molar enthalpy of mixing of the liquid mixtures BaO-B2O3 and CaO-B2O3 was measured calorimetrically in the composition range from about 30 to 100 mol% B2O3 at temperatures of 1551 and 1725 K, respectively, and the partial molar enthalpy of mixing of the component oxides was obtained by the method of intercepts. The curves representing the functional dependence of the integral and partial enthalpy of mixing on composition are composed of three distinct sections separated one from the other by "singularities" (points of inflection, maxima, etc.). The possible significance of this as well as the relationship between the thermochemical and structural properties of the liquid mixtures are discussed on the basis of information, reported for the structure of these mixtures in the literature.