High entropic coatings FeCrNiTiZrAl and their properties

In our proposed empirical model, the anisotropy of the surface energy and the thickness of the surface layer of the high-entropy FeCrNiTiZrAl alloy are calculated. The thickness of the surface layer of this alloy is about 2 nm, which is an order of magnitude greater than the thickness of the surface layer of complex crystals, but is of the same order of magnitude as that of metallic glasses. The hardness and other properties of the high-entropy alloy are the same as for metallic glasses, but are 2-3 times higher than the hardness of stainless steels. The surface energy of the high-entropy FeCrNiTiZrAl alloy is about 2 J/m2, which corresponds to the surface energy of magnesium oxide and other crystals with a high melting point. However, unlike these crystals, the friction coefficients of a high-entropy alloy (~ 0.06) are much lower than that of ordinary steels (~ 0.8). We have theoretically shown that the friction coefficient is proportionally dependent on the surface energy and inversely proportional to the Gibbs energy, which significantly decreases for a high-entropy alloy, leading to low friction. The high hardness and low coefficient of friction of the high-entropy alloy facilitates the deposition of coatings from them on structural metal products, which contributes to their widespread use.

The guest polymer effect on the dissolution of drug–polymer crystalline inclusion complexes

Guest polymers have significant influence on the dissolution of drug–polymer inclusion complex crystals.

Optoelectronic Properties of Ternary Tetrahedral Semiconductors

The dielectric interpretation of crystal ionicity evolved by Phillips and Van Vechten (P.V.V) has been utilized to evaluate various ground state properties for broad range of semiconductors and insulators. Although, the relevance of P.V.V dielectric theory has been restricted to only simple ANB8-N structured compounds, which have a particular bond. Levine has broadened P.V.V. theory of ionicity to multiple bond and complex crystals and evaluated many bond parameters for ternary tetrahedral semiconductors. Some other researchers have extended Levine’s work with a concept of ionic charge product and nearest neighbour distance to binary and ternary tetrahedral crystals to evaluate the ground state properties. In this paper, a new hypothesis of average atomic number of the elements in a compound has been used to understand the some electronic and optical properties such as ionic gap (Ec), average energy gap (Eg), crystal ionicity (fi), electronic susceptibility (χ), and dielectric constant (ϵ) of ternary tetrahedral (AIIBIV and AIBIII) semiconductors. A reasonably acceptable agreement has been noticed between our evaluated values and other researchers reported values.

Solvatomorph and polymorph screening of clopamide drug and its copper(ii) complex crystals

The anhydrate and hemihydrate structures of the marketed drug, clopamide, are described the first time. Structural landscape of its copper complexes is presented: three polymorphic modifications and an isostructural series of its alcohol clathrates.

Halogen bonding in crystals of free 1,2-diiodo-ethene (C2H2I2) and its π-complex [CpMn(CO)2](π-C2H2I2)

Abstract1,2-trans-diiodo-ethene (C2H2I2) – is an overlooked halogen bond donor, which demonstrate the distinct similarity of the geometry and directionality of I···I halogen bonds around the iodine atoms in its native and CpMn(CO)2(C2H2I2) π-complex crystals. Distortion of the planar geometry of C2H2I2 upon the π-coordination result the distortion of the native planar layered geometry of C2H2I2, so that [CpMn(CO)2](π-C2H2I2) features more complex I···I XB assisted 3D network. Unusual structural parallels between the native C2H2I2 crystals and solid iodine are discussed.