By means of the density functional theory (DFT) method, the electronic structure of the new tin monosulfide polymorph π-SnS has been calculated, its unit cell parameters have been optimized, and the relative enthalpy of formation and bulk modulus have been evaluated and compared with known and well-characterized crystalline and two-dimensional SnS modifications. It has been demonstrated that the π-SnS polymorph ranks next in stability to thermodynamically stable α-SnS. The new modification is predicted to be a semiconductor with a wider band gap than for α-SnS. It has been shown that identification of π-SnS in nanocrystalline SnS samples by X-ray crystallography could be considerably complicated by overlapping with broadened reflections of α-SnS.

Imogolite—a congregation of aluminosilicate nanotubes—has shown a great promise for fabrication of advanced materials. Imogolite nanotubes hold the record narrow diameters distribution and demonstrate one of the highest curvatures among noncarbon nanotubes. Current experimental and theoretical prospects for their modification are related mostly to surface functionalization or to progressive Si substitution on Ge, whereas a doping of Al sublattice is steadily neglected. The empirical rules of Hume–Rothery disallow such doping due to a large size mismatch between Al3+ and the majority of metal cations. Using the quantum‐chemical calculations, herein, the difference in coordination environment is unveiled for 12 sorts of trivalent cations at octahedral Al sites in both a highly curved imogolite layer and the flat gibbsite layer. The curvature of natural imogolite acts provoking for violation of the Hume–Rothery rules, sterically promoting the doping of Al sublattice by cations with radii 1.0–1.2 Å typical for rare‐earth elements. Theoretically, the synthesis of a metal‐doped imogolite is restricted only by the overlap of the phase stability fields for precursor reactants or by kinetic factors. This study might be inciting for the synthesis of chemically modified imogolite and related Ge‐imogolites.

Molybdenum disulfide is a title compound among the layered metal dichalcogenides, being a prominent tribological agent and vital platform for catalysts. The properties of a MoS 2 layer can vary widely, depending upon polymorphic composition. Here, using the density-functional theory calculations, the potential energy surfaces for polymorphic H-and T-MoS 2 layers are mapped. While the energy barriers for H→T and T(T )→H transitions are found to be in fair agreement with previous studies which employed the nudged elastic band method, the bird's-eye view at the energy landscape of MoS 2 layer has disclosed the as-yet undescribed energy plateau attributed to an intermediate -square lattice of MoS 2 layer (S-MoS 2 ). The stability, structural and electronic properties of S-MoS 2 are discussed in comparison with those for H-and T-MoS 2 layers.

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