Crystal structure of bis­muth-containing NdFe₃(BO₃)₄ in the temperature range 20–500 K

An accurate single-crystal X-ray diffraction study of (Nd_0.91Bi_0.09)Fe₃(BO₃)₄ was performed in the tem­per­ature range 20–500 K. The tem­per­ature-dependent behaviour of the structural parameters is com­pared with the behaviours of other rare-earth iron bor­ates.

A general method for searching for homometric structures

A method for searching for homo­metric structures using symmetry operations has been developed. The method was applied to the Inorganic Crystal Structure Database and homo­metric structures are found for 37 reported structures.

Polytypism in mcalpineite: a study of natural and synthetic Cu₃TeO₆

The crystal structure of the low-temperature 2O polytype of Cu^II₃Te^VIO₆ (the mineral mcalpineite) has been determined by 3D electron diffraction (3D ED) and Rietveld refinement following X-ray powder diffraction (PXRD).

Fast crystal growth of amorphous nimesulide: implication of surface effects

Fiber growth of nimesulide, a precursor of glass-to-crystal growth in supercooled liquid, is reported.

Phase transitions and (p–T–X) behaviour of centrosymmetric perovskites: modelling with transformed crystallographic data

The structures of centrosymmetric perovskites (ABX₃) are modelled by transforming crystallographic data into a Cartesian space defining BX₆ octahedral tilting and distortion. Structural evolution and phase transitions under variable (p–T–X)-conditions are analysed and predicted.

Polymorphism, polytypism and modular aspect of compounds with the general formula A₂M₃(TO₄)₄ (A = Na, Rb, Cs, Ca; M = Mg, Mn, Fe³⁺, Cu²⁺; T = S⁶⁺, P⁵⁺): order–disorder, topological description and DFT calculations

The replacement of Na⁺ by alkali metal cations with larger ionic radii (Rb⁺ and Cs⁺) in compounds with the chemical formula A₂Mg₃(SO₄)₄ significantly changes the topology of the heteropolyhedral MT framework.

1-Allyl-4-hy­droxy-2,2-dioxo-N-(4-meth­oxy­phenyl)-1H-2λ⁶,1-benzo­thia­zine-3-carboxamide: polymorphic transition due to grinding with the loss of the biological activity

Two polymorphic forms of 1-allyl-4-hy­droxy-2,2-dioxo-N-(4-meth­oxy­phenyl)-1-2λ⁶,1-benzo­thia­zine-3-carboxamide (a structural analogue of piroxicam) have different crystal structures from the energetic viewpoint and different biological activity. A slow polymorphic transition after grinding results in the loss of the biological activity.

The role of local heteropolyhedral substitutions in the stoichiometry, topological characteristics and ion-migration paths in the eudialyte-related structures: a qu­antitative analysis

Topological analysis of the heteropolyhedral MT framework (where M and T are octahedral and tetrahedral cations, respectively) in the eudialyte-type structure and its derivatives was performed based on a natural tiling analysis of the 3D cation nets with the ToposPro software using both the standard representation and the 0-1-2-free representation.

FOX-7 high-energy-density material: thermal expansion and phase transitions revisited

Variable-temperature single-crystal synchrotron diffraction experiments treated with the Gandolfi method reveal the structural phase transitions and thermal expansivities for the energetic material FOX-7.