Method of the correlative optimization of heat capacities of isostructural compounds

A semi-empirical approach to the critical analysis of thermodynamic data is proposed and applied in this work. As an example, sets of numerous experimental and calculated heat capacity values of 16 isostructural AIIIBV compounds were taken from the literature. A critical analysis of heat capacities of 16 AIIIBV compounds was then made based on the correlative optimization method. As a result, a set of mutually agreed equations CPo=a+b·10-3-c·105·T-2 was proposed to describe the heat capacities of these phases. Two continuums of relations CP(T)CP(T)vs. logarithm of the sum of atomic numbers of elements A and B were obtained for the AIIIBV phases, of both sphalerite and wurtzite types, in the temperature range from 260 to 1500 K. Based on the proposed equations, heat capacity values were predicted for the previously unstudied (or poorly studied) phases TlN and AlP within the temperature ranges from 260 to 1018 K from 260 to 1500 K, respectively. The proposed correlative method of thermodynamic functions can be applied to other different groups of isostructural organic and inorganic compounds.

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► Optimization of heat capacities is proposed for 16 AIIIBV phases.
► The new correlation approach is based on the similarity of thermodynamic properties of isostructural phases.
► Heat capacities are calculated for previously poorly studied phases TlN and AlP.