Heat Capacities Cp(T) of the Isostructural Sphalerite Phases as a Single System in Solid State

Vassiliev, V.P.

Автор: Vassiliev Valery P.
Журнал: Journal of Materials Sciences and Applications
Том: 6
Год издания: 2022
Издательство: JScholar
Местоположение издательства: USA
Первая страница: 1
Последняя страница: 16
Аннотация: The standard thermodynamic constants are important for all branches of science. The correct description of heat capacities in a wide range of temperatures is to find a rigorous description to this still unsolved problem. A fragmental description of some phases is like a vision of one part of a large mosaic picture. A single description of the heat capacity or other property of a phase of any isostructural series 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 as 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 (α) or the Sommerfeld constant. 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. 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. The maximum heat capacity of flerovium can be taken as a constant value of 30.5 J·mol-at-1·K-1 with an accuracy of 1%. As the temperature decreases, this value slowly decreases (within 1%), and then, when it approaches to 0 K, it drops sharply to 0 J·mol-at-1·K-1. 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.
Добавил в систему: Васильев Валерий Петрович

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Heat Capacities Cp(T) of the Isostructural Sphalerite Phases as a Single System in Solid Stateстатья

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