Crystallization induced by fungi and bacteria

The patterns of microbial crystallization are controlled by the chemical composition of biofilms associated with environmental exposure and the activity of microorganisms. The nutrition of microorganisms changes the oxalic acid and extracellular polymer substance content in the products of microbial metabolism, which significantly affects the medium pH promoting either the oxalate or carbonate crystallization.

Review of honeycomb-based Kitaev materials with zigzag magnetic ordering

Two-dimensional honeycomb materials as candidates for Kitaev quantum spin liquids are examined, focusing on their single-k zigzag magnetic structures and the derived multi-k variants. A comprehensive overview of these systems is provided, offering detailed crystallographic insights and highlighting their role in advancing both theoretical and experimental research.

SARAh – web representational analysis

The online software server SARAh—webRepresentational Analysis is introduced. The new suite of web apps carries out a range of calculations based on representation theory for the modelling of possible magnetic structures, their refinement from neutron scattering data and the analysis of other problems in condensed matter.

Modulation of the modulated magnetic structure of an Ho i-MAX phase described by a magnetic (3+2)-dimensional superspace group

A rare complex incommensurate magnetic structure, an amplitude-modulated structure which itself is modulated, was determined in the Ho-based i-MAX phase (Mo_2/3Ho_1/3)₂GaC. It represents a particularly distinctive case of a 2-k magnetic structure with no symmetry relation between the propagation vectors.

Photoelasticity of crystals with the scheelite structure: quantum mechanical calculations

The methodology proposed combines the DFT calculations and photoelasticity caused by uniaxial compression of the crystal lattice, with particular emphasis on its anisotropy. It can be considered as part of optical engineering aimed at preliminary assessment of the photoelastic properties of crystal materials, thus assisting in their selection for synthesis and relevant applications.

Selective acceleration and inhibition of crystal growth of glass carbamazepine by low-concentration poly(ethylene oxide):effects of drug polymorph

Low-concentration poly(ethylene oxide) effects both the surface and bulk crystal growth of carbamazepine polymorphs. These polymorph-dependent effects are mainly attributed to the polymer enrichment at the interface and different crystal surface–polymer interactions.

A rare case of Na/Zn isomorphism in the crystal structure of non-centrosymmetric zincophosphate Na₅Zn[Zn(PO₄)₃]

Na₅Zn[Zn(PO₄)₃] with a new structure type represents a rare case of Na/Zn isomorphism.

Structural and magnetic phase transitions in Eu_1–xLa_xFe₃(BO₃)₄ (x = 0, 0.18)

The structural behaviour of EuFe₃(BO₃)₄ and lanthanum-doped EuFe₃(BO₃)₄ crystals has been studied with respect to tem­per­a­ture using X-ray fluorescence analysis, single-crystal X-ray diffraction, Mössbauer spectroscopy and specific heat capacity measurements. Structural and magnetic phase transitions have been discussed.

Crystal structure and doping in synthetic enstatite: an analysis of Li/Fe³⁺-doped single-crystal samples

Several Li⁺/Fe³⁺-doped Pbca orthoenstatite and Pbcn protoenstatite crystals are characterized revealing that varying levels of doping preferentially affect the py­rox­ene topologies.

Structural and theoretical studies of amantadinium fenamates

New crystals of salts of fenamic acid–amantadine and tolfenamic acid–amantadine are presented. Structural studies and theoretical analysis using quantum theory of atoms in molecules and non-covalent interaction methods were performed to investigate weak interactions that are found to be crucial for the stabilization of the studied crystals.

High-pressure and low-tem­per­ature behaviour of organic ferroelectric (R)-3-quinuclidinol

Pressure-induced structural strain in (R)-3-quinuclidinol crystals is analysed under pressure and com­pared with structural strain on cooling.

Accurate and efficient representation of intramolecular energy in ab initio generation of crystal structures. Part III: partitioning into torsional groups

An algorithm for dramatically reducing the number of QM calculations required to derive a flexibility model of molecules, whilst retaining the accuracy necessary for Crystal Structure Prediction, is presented. Torsional group partitioning can make previously inaccessibly large molecules tractable, and molecule 26 from the blind tests, and safinamide, are demonstrated as use cases

Structural studies of hydrated rare earth nitrates within the stereoatomic model of crystal structures

Several isotypic and morphotropic series are are described. Coordination numbers of metal atoms, variation of bond lengths, coordination modes of ligands and combinatorial topological types of Voronoi–Dirichlet polyhedra are discussed.

Electron density distribution in bis­(guanidinium) disodium hypodiphosphate heptahydrate, (CH₆N₃)₂Na₂(P₂O₆)·7H₂O

The nature of contacts within bis(guanidinium) disodium hypodiphosphate heptahydrate is explored using electron density distribution analysis.

Crystallography of the litharge to massicot phase transformation from neutron powder diffraction data

The crystallographic phase change from tetragonal litharge to orthorhombic massicot (PbO) between ambient temperature and 925 K is studied. The planar (001) layers of external PbO₄ square pyramids and internal OPb₄ tetrahedra in litharge (α-PbO) are converted into equivalent deeply corrugated (100) layers in massicot (β-PbO) at temperatures between 850 and 925 K. The layers in both compounds are held together by van der Waals forces between Pb lone pairs pointing directly or indirectly into the gap.