Investigation of interactions in Lewis pairs between phosphines and boranes by analyzing crystal structures from the Cambridge Structural Database

The differences in crystallographic parameters of various phosphine–borane pairs have been described. It was found that truly frustrated Lewis pairs could not be isolated. This report also suggests a revising of the nomenclature of the pairs.

Theory of order–disorder phase transitions of B-cations in AB′_1/2B′′_1/2O₃ perovskites

A theory of order–disorder phase transitions of B-cations in AB′_1/2B′′_1/2O₃ perovskites is developed which allows reliable estimation of the phase transition temperatures and of the reduced lattice constants of such compounds.

Crystal structures of K₂[XSi₅O₁₂] (X = Fe²⁺, Co, Zn) and Rb₂[XSi₅O₁₂] (X = Mn) leucites: comparison of monoclinic P2₁/c and Iad polymorph structures and inverse relationship between tetrahedral cation (T = Si and X)—O bond distances and intertetra­hedral T—O—T angles

Crystal structures for synthetic analogues of the tectosilicate mineral leucite (KAlSi₂O₆) with stoichiometries of K₂X²⁺Si₅O₁₂ (X = Fe²⁺, Co, Zn) and Rb₂X²⁺Si₅O₁₂ (X = Mn) were refined from X-ray powder diffraction data. Structures refined in P2₁/c have ordered Si and X cations on the tetrahedral sites, whereas structures refined in have disordered Si and X cations. These leucite structures show an inverse relationship between the tetrahedral T—O distances and the intertetrahedral T—O—T angles.

Crystal structure analysis of a star-shaped triazine compound: a combination of single-crystal three-dimensional electron diffraction and powder X-ray diffraction

The solid-state structure of a star-shaped triazine compound is determined from a powder sample by exploiting the respective strengths of single-crystal electron diffraction and powder X-ray diffraction data, confirming that the symmetry of the crystal packing allows for nonlinear optical effects.

Structure of russellite (Bi₂WO₆): origin of ferro­electricity and the effect of the stereoactive lone electron pair on the structure

The structure of the low-temperature polar (orthorhombic) phase of russellite (Bi₂WO₆) was re-examined with single-crystal X-ray diffraction. The position of the stereochemically-active lone pair of electrons of bis­muth was found on a line running through the Bi sites in the b-axis direction. The ferroelectricity of the compound was ascribed to the strong tendency of bis­muth to form shorter Bi—O bonds, and this resulted in the cooperative shift of tungsten.

A crystallographic and thermal study of pridinol mesylate and its monohydrated solvate

The dehydration of the monohydrate salt of pridinol mesylate is strongly dependent on the heating rate, slow rates leading to a solid–solid process, intermediate rates to coexistence with the hydrate and faster heating to complete melting, without generation of the anhydrous solid in the water-loss process.

Hydro­phobic dipeptides: the final piece in the puzzle

The crystal structure of L-valyl-L-leucine aceto­nitrile solvate presented here completes a systematic investigation of dipeptides constructed from the five nonpolar amino acids alanine, valine, isoleucine, leucine and phenyl­alanine. The crystal packing arrangements and hydrogen-bonding preferences of this unique group of substances are reviewed.

Chemistry of Carbon Nanostructures