ИСТИНА

The standard thermodynamic constants are important for all branches of science. The correct description of the heat capacities in a wide temperature range for finding a solution. A fragmental description of some phases is like a vision of one part of a large mosaic picture. A single description of such a phase does not allow one to see the integrity of the entire ensemble. The nontrivial concept permitted us the possibility of finding a simple solution to this issue. This solution helped describe the specific heat in a wide temperature range of a large class of isostructural sphalerite phases as a single system unambiguously. The 4th group of pure elements in addition to diamond, silicon, germanium, alpha tin, and diamond-like lead was taken as the base. Flerovium (114Fl) closes this group. There should be no other elements in this group according to the fine structure constant or the Sommerfeld constant α. As a consequence, the limiting value of the heat capacities of phases with a sphalerite structure falls on the 114th element (114Fl) and has a value of Cp = 30.50.3 J · mol-at-1 · K-1. This value was obtained as a maximal virtual point Cp of the last elements (114Fl) of the IV group and corresponds to Ln (Cp / R) = 1.300.01 for the isotherms Ln (Cp / R) vs Ln (N), where N is an atomic number of an element of the IV group or the sum of the atomic numbers of AIIIBV or AIIBVI compounds per mole-atom. The common point of heat capacity attributable to flerovium is obtained from the linear equations Ср/R vs Ln(N) at low temperatures from 25 to 35K (Fig.1). If we consider only pure elements of the 4th group: silicon, germanium and alpha-tin, then flerovium closes this group, and there are no other elements behind it according to the constant (alpha) of Sommerfeld. Moreover, the "bend angle" of the heat capacity Cp(T) from Si to Fl approaches the limit of 90 degrees. With an accuracy of up to 1%, the limiting heat capacity of flerovium can be taken as a constant. Approaching up to 0 K, the heat capacity of flerovium drops sharply to 0. The proposed model was taken as an ideal crystal that does not have any foreign inclusions, defects, or dislocations. Thus, it is quite obvious that other types of heat capacities of structural compounds will have their own maximum values Cp. The proposed method can be used to analyze the heat capacities of the differ classes of isostructural phases. [1] Vassiliev, V.P.; Taldrik, A.F. Description of the heat capacity of solid phases by a multiparameter family of functions. J. Alloys Comp. 2021, 872, 159682. DOI: 10.1016/j.jallcom.2021.159682 [2] Vassiliev, V.P.; Optimization of the Heat Capacities of Diamond-Like Compounds. J. Mat. Sci. Eng. B 11 2021, 4-6, 76-80. DOI: 10.17265/2161-6221/2021.4-6.004