Electron diffraction of ABX₃ perovskites with both layered ordering of A cations and tilting of BX₆ octahedra

ABX₃ perovskites with both tilting of BX₆ octahedra and layered ordering of A cations are examined on the basis of group–subgroup relations. A systematic method for distinguishing the space groups by electron diffraction is proposed.

The incommensurately modulated crystal structure of β-Pb₂BiVO₆: interpretation of the phase transition α → β → δ and conduction properties of related materials

The incommensurately modulated structure of the β-Pb₂BiVO₆ polymorph has been solved using a combination of X-ray single-crystal diffraction, powder diffraction and transmission electron microscopy observations. Phase transitions between the different polymorphs have been characterized both by high-temperature X-ray diffraction and by ionic conductivity measurements.

Analysis of ion-migration paths in inorganic frameworks by means of tilings and Voronoi–Dirichlet partition: a comparison

Two methods by Voronoi–Dirichlet polyhedra (Voronoi–Dirichlet partition) or tiles (tiling) based on partitioning space are compared to investigate cavities and channels in crystal structures. Both advantages and restrictions of the methods are discussed with respect to fast-ion conductors and zeolites.

Crystal structures and cation ordering in Cs₂MgSi₅O₁₂, Rb₂MgSi₅O₁₂ and Cs₂ZnSi₅O₁₂ leucites

High-resolution synchrotron X-ray powder diffraction and ²⁹Si MAS NMR spectroscopy have been used to determine and refine the crystal structures of synthetic analogues of the mineral leucite.

Trigonal structures of ABe₂BO₃F₂ (A = Rb, Cs, Tl) crystals

The crystal structures of RbBe₂BO₃F₂ and CsBe₂BO₃F₂, previously determined in the space group C2, were redetermined in the space group R32. The structure of the novel compound TlBe₂BO₃F₂ was also determined in R32 and structural trends within this fluoroberyllium borate family are discussed.

Atomic displacements at and order of all phase transitions in multiferroic YMnO₃ and BaTiO₃

A previously unknown aristotype phase of ferroelectric YMnO₃, with a melting point of ∼ 1600 K, is predicted on the basis of the coordinate analysis of its known phases and of those in multiferroic BaTiO₃.

Structural elucidation of the Bi_2(n + 2)Mo_nO_6(n + 1) (n = 3, 4, 5 and 6) family of fluorite superstructures by transmission electron microscopy

The basic cationic structure of three different members of a new family of anionic conductors, Bi_2(n + 2)Mo_nO_6(n + 1) (n = 4, 5 and 6), was elucidated mainly by means of high-resolution electron microscopy images based on the previously known structure of the n = 3 phase, Bi₁₀Mo₃O₂₄. The models proposed have been successfully tested by HRTEM (high-resolution transmission electron microscopy) image simulation, and electron and powder X-ray diffraction simulations.

Inverse bilayer structure of mononuclear Co^II and Ni^II complexes of the type M(H₂O)₃(SO₄)(4-CNpy)₂

Hydrogen bonds and π–π interactions between nitrile triple bonds in a pair of isostructural cobalt(II) and nickel(II) complexes of the type [M(H₂O)₃(SO₄)(4-CNpy)₂], M = Ni, Co, lead to a novel inverse bilayer structure.

Polymorphism in the spin-crossover ferric complexes [(TPA)Fe^III(TCC)]PF₆

The spin-crossover properties of monoclinic and orthorhombic polymorphs of a cationic iron(III) complex are compared. The packing within the ionic layers in the two polymorphs is very similar, but the layer stacking differs.

Structures of strontium diformate and strontium fumarate. A synchrotron powder diffraction study

The structures of β- and δ-strontium diformate, and α- and β-strontium fumarate all show a diamond-like strontium arrangement as in strontium acetylene dicarboxylate.

Transferability and reproducibility in electron-density studies – bond-topological and atomic properties of tripeptides of the type L-alanyl-X-L-alanine

Experimental electron-density results of eight tripeptides of the type L-Ala-X-L-Ala (AXA) and the corrresponding theoretical results of 20 AXA tripeptides (X varied over all 20 genetically encoded amino acids) were analyzed to provide a quantitative measure for transferability of bond-topological and atomic properties.

Synthesis, crystal structure and spectroscopic properties of a novel carbacylamidophosphate: N-(3-nitro­benzoyl)-N′,N′′-bis­(tert-butyl)phosphoric tri­amide

The new compound N-(3-nitrobenzoyl)-N′,N′′-bis(tert-butyl)phosphoric triamide has been synthesized and characterized. Structural properties were analyzed using single-crystal X-ray diffraction, vibrational spectra and theoretical calculations.

On the polymorphism of benzocaine; a low-temperature structural phase transition for form (II)

A low-temperature structural phase transition is observed for form (II) of benzocaine (BZC). The new structure [form (III)] is twinned corresponding to a 2₁ screw rotation parallel to the direction of displacements for hydrogen-bonded ribbons of molecules. No similar phase transition is observed for form (I).

Structures of the pseudo-trigonal polymorphs of Cu₂(OH)₃Cl. Corrigendum

A corrigendum to the paper by Malcherek & Schlüter (2009), Acta Cryst. B65, 334–341.

Molecular Clusters. A Bridge to Solid-State Chemistry