Analysis of physicochemical properties in covalent network chalcogenide glasses (ChGs): critical review of theoretical modeling of chemical bond approach

Abstract

The Group 16 elements are frequently named as chalcogens ('ore builders'). From the geographical point of view, they are known as chalcophiles which are the soft elements (keeping in mind the terminology of the hard/soft acids and bases concept). In the geographical sense, chalcophiles preferably form minerals with sulfur (S), selenium (Se) and tellurium (Te). However, oxygen (O) tends to bind preferably to lithophiles, which are hard elements such as the alkali metals, early transition metals, and silicon. The special position of oxygen amongst the chalcogen elements is its association with its very high electronegativity, which in turn correlates with its high ionization energy and the small atomic radius; which makes it difficult for oxygen to act as a central atom in electron-rich multicentre bonds. In the present script, we have reviewed the models for theoretical prediction of some significant physical parameters i.e. coordination number, constraints, density, molar volume, cohesive energy and heat of atomization etc. for the three generations of Se rich multicomponent glasses are presented. The present theoretical study of the multi-component chalcogenide glasses reveals that there is a significant change in the structural environment of the three generations (binary, ternary and quaternary systems) due to rigidity percolation.

Impact of micro-indentation load/time and Zinc concentration on the thermo- mechanical characteristics of amorphous Se78Te20Sn2 alloy

“…In glassy materials, density is closely connected to the average coordination number, which characterizes the arrangement of atoms in the material. By employing the following formula, the density of chalcogenide glasses can be determined [52][53][54]:…”

“…the fraction of mass (m i ) and the density (d i ) associated with each specific structural unit within the material. Considering the density equation mentioned earlier, we can derive the relationship between molar volume by expressing it as follows [52][53][54]:…”

Thermal analysis of novel third-generation phase-change materials with zinc as a chemical modifier

“…We have used the following relation for the determination of the average heat of atomization H̄ A of the samples in the present study: 61 Here H Se , H Te , H Sn , and H Zn are the respective atomization heat values of Se, Te, Sn, and Zn in the present samples (0 ≤ x ≤ 6) of the Se 78− x Zn x Te 20 Sn 2 system, while j , k , l , and m are the corresponding concentrations. The dependency of H̄ A on the zinc content is revealed in Fig.…”

Improvement in spectral range of Sb 2 Se 3 absorption layer on Bi addition

“…where M i is the molecular weight of the i th constituting element and X i is the atomic percentage in the sample. It can be observed from table 2 that the values of molar volume increase with increase in the Bi content [37].…”

“…This in turn will increase the electrical conductivity. As a result, the mean atomic volume increases, and the compactness value decreases [37].…”