For instance, the chalcogenide compounds B 6S and B 6Se have already been synthesized by a chemical reaction process at high pressures. The structure of the B 12 icosahedral boron network is also found in some other compounds similar to B 12S and B 12Se. The author reported that both chalcogenides belong to a family of hard compounds. (7) In 2021, Solozhenko (15,16) measured the microhardness of 3D B-rich compounds B 12S and B 12Se experimentally using Vicker hardness ( H V) and Knoop hardness ( H K) methods and also studied the oxidation resistance by thermal analysis. Furthermore, only the bulk modulus of B 12Se among all mechanical properties has been studied using the third-order BirchвЂ“Murnaghan equation of state so far. The stoichiometric ratio of the chalcogenides has been computed. With the help of powder X-ray diffraction and Raman spectroscopy, it is found that the crystal structure belongs to rhombohedral symmetry with the space group R3М… m (no. (8) have synthesized 3D B-rich compounds B 12S and B 12Se using a chemical reaction process at a pressure of 6 GPa and a temperature of 2500 K. (1в€’3,5,7в€’14) Very recently, Cherednichenko et al. Recent discovery of B-rich compounds has received considerable research attention for the betterment of the physical properties in these days. (1,6) Among the B-rich compounds, the B-rich solids with icosahedral clusters (1,6,7) structurally derived from О±-rhombohedral boron (О±-rh boron) offer some industrial potential candidate materials similar to boron carbide, boron sub-oxide and boron sub-phosphide, REB 15.5CN, REB 22C 2N, and REB 28.5C 4 (RE = heavy rare-earth element, Y, and Sc). (1в€’6) Many interesting physical properties such as high hardness, useful electronic properties, low mass density, a very high melting point, and excellent thermal stability and chemical inertness of B-rich compounds have gained extra attention of the materials science and engineering research community in view of the potential technical applications. Such useful features of the compounds under investigation show promise for applications in optoelectronic and mechanical sectors.Д«oron (B)-rich compounds having structural units of B 12 closed cage clusters are novel systems attracting significant interest of the research community. These compounds possess bulk optical anisotropy, and excellent absorption coefficients in the visible-light region along with very low static values of reflectivity spectra (range of 7.42вЂ“14.0% using both functionals) are noted. The optical properties such as the dielectric function, refractive index, absorption coefficient, reflectivity, and loss function are characterized using GGA-PBE and HSE06 methods and discussed in detail. The electrons of the B 12Se compound show a lighter average effective mass than that of the B 12S compound, which signifies a higher mobility of charge carriers in B 12Se. The energy gaps using local density approximation (LDA) and generalized gradient approximation (GGA) are found to be significantly lower. Indirect band gaps of B 12S (2.27 eV) and B 12Se (1.30 eV) are obtained using the HSE06 functional. The melting point, T m, for the B 12S and B 12Se compounds suggests that both solids are stable, at least up to 42 K, respectively. Reasonably good values of fracture toughness and the machinability index for B 12X (X = S and Se) are reported. The origin of differences in hardness is explained on the basis of density of states near the Fermi level. Furthermore, the elastic moduli and hardness parameters are calculated, which show that B 12S can be treated as a prominent member of the hard materials family compared to B 12Se. The considered materials are mechanically stable, brittle, and elastically anisotropic. The consistency of the obtained crystal structure with the reported experimental results has been checked in terms of lattice parameters. The effects of exchange and correlation functionals on these properties are also investigated. In this regard, we report the electronic, optical, and mechanical properties of recently synthesized boron-rich chalcogenide compounds B 12X (X = S and Se) using density functional theory for the first time. Boron-rich chalcogenides have been predicted to have excellent properties for optical and mechanical applications in recent times.

Evc prototype 1