Three symmetry-raising phase transitions of anilinium tetrafluoroborate between room temperature and 490 K have been structurally characterized using powder and single-crystal diffraction, dielectric measurements, NMR and group–subgroup relationships.

Amplitudes for resonant X-ray diffraction by collinear antiferromagnet Li2Ni3P4O14 that include permitted Dirac multipoles, e.g. anapoles, are investigated. Chiral signatures for the rotation of X-ray helicity are described.

A reconsideration of the crystal structures of mcgovernite and carlfrancisite gives noncentrosymmetric structures with ordered planar defects instead of random site disorder in centrosymmetric ones.

Two-dimensional van der Waals layered compound CuVP2S6 is studied by transmission electron microscopy and single-crystal X-ray diffraction. Rotational microtwin structures, which may be typical and characteristic of two-dimensional van der Waals compounds, are observed.

Three new Schiff base ligands are characterized. The presence of intra- and intermolecular interactions in the compounds are established by QTAIM theory and noncovalent interaction plot computational method. Hirshfeld surface analysis reveals that the most abundant intermolecular contacts are H⋯H contacts. The interaction energies of the dimer associates of the compounds through the intermolecular interactions in their solid-state are obtained by energy decomposition analysis via natural orbitals for chemical valence theory.

The complex stacking disorder of 2,3-dihydroxy-1,3,4-trimethyl-6-oxo-1,4-cyclohexadiene-1-carboxylic is analyzed by applying the order–disorder theory and its diffuse scattering is interpreted using a growth model.

The stable epitaxial growth of silicene on MoS2 requires both van der Waals and covalent interactions – without them, the silicene collapses into a disordered state. These findings offer important insights into designing stable silicene/MoS2 heterostructures for future nanotechnology applications.

Crystals of flocculosin-A, the major antifungus compound from Anthracocystis flocculosa, are optimised using a cyclic temperature control.

This study highlights how solvent properties, host–guest interaction energies and packing preferences govern the solid-state organization of tert-butyl­calix[6]arene, a macrocycle of importance in separation, molecular recognition and supramolecular chemistry.

The quantum crystallography approach used here reveals the fine features of the interatomic interactions of different nature in [Co(NH3)5NO2]ClNO3 and [Co(NH3)5ONO]ClNO3 crystals and provides a better insight into the role of the crystalline environment in the intramolecular nitro–nitrito linkage photoisomerization.

Restraints for atomic displacement parameters of hydrogen atoms in Hirshfeld atom refinement are tested using two polymorphs of the water-rich l-Asp-l-Asp-l-Asp (DDD) crystal structure.

The crystal structure of the mixed tetrahedral–octahedral framework silicate Cs4Ca[Si8O19] has been solved. A topological analysis of the present compound and other interrupted framework silicates is ...

A unique phase transition, twinning and ferroelastic domain structure in [NH3(CH2)2NH3]2[ZnBr4]Br2 is found. The new additional domain structure is observed at the phase transition on heating, which is preserved after cooling to room temperature.

1,2-Bis(3,5-di­methyl-2-thienyl)perfluoro­cyclo­pentene formed its own spherulites by sublimation onto the hydro­philic surfaces of the (0001) planes of α-quartz and sapphire substrates. The formation of different morphologies of these spherulites was attributed to the surface properties of each substrate. Depending on the morphology of the spherulites, hollow rod crystals with cross sections of different sizes and shapes and branching structures were generated on the surfaces of the spherulites.

Tetragonal YxOs4B4 (x = 1.161) is an incommensurate composite of columns of Y atoms in a three-dimensional Os4B4 framework. The structure was refined using the superspace approach.

The structure of Ni3V2O8 was studied using X-ray diffraction at temperatures of 299 and 1323 K. No phase transition at high temperature is observed. The variation in V—O bond length is small as compared with the Ni—O bond due to its high rigidity.

In-situ diffraction measurements reveal that magnesium chloride forms a unique high-pressure phase, a heptahydrate, above 2 GPa. The hydrogen-bonding structure appears to contain orientational disorder.

We show that the interplay of multiple magnetic sublattices in Er2CuMnMn4O12 leads to four magnetic phase transitions characterized by the onset of ferrimagnetic order, spin-reorientation, spin canting, and the polarization of Er ions. While we elucidate numerous features of this complex magnetic system, the exact nature of the low-temperature coupling between erbium and manganese, and the origin of a k = (0, 0, ½) modulation, remain intriguing topics for future studies.

The results of the seventh blind test of crystal structure prediction are presented, focusing on structure ranking methods.

The results of the seventh blind test of crystal structure prediction are presented, focusing on structure generation methods.

Density-functional calculations using numerical atomic orbitals and the exchange-hole dipole moment dispersion model were applied to the energy ranking stage of the seventh crystal structure prediction blind test. This methodology gave successful predictions of the experimentally isolated polymorphs as being low in energy for three of the compounds considered, and for one additional compound upon inclusion of a vibrational free-energy correction.

A design is tested for a polymorph search algorithm relevant for enhanced sampling of crystal structures based on the relation between internal molecular structure variables and corresponding crystal polymorphs as representative of the inherent vapor to crystal transitions that exist in nature. Molecules are represented as extended variables within a thermal reservoir. Unit-cell variables are generated using pseudo-random sampling incorporating a harmonic coupling to extended variables.

The conformational energies and crystal energy landscapes for molecules XXXI and XXXII from the seventh blind test of crystal structure prediction are investigated with a variety of electronic structure methods. Whereas molecule XXXI can be modeled relatively straightforwardly, molecule XXXII proves challenging even for state-of-the-art quantum chemistry techniques.

The crystal structure of calcium atorvastatin trihydrate was redetermined from previously published synchrotron powder diffraction data to give a much-improved agreement with two independent density-functional theory calculations.