A new look at two polymorphic crystal structures of di­benzoyl­methane: relationship between the crystal packing and the hydrogen atom position revealed by quantum chemistry and quantum crystallography methods

Crystal structures of two polymorphic forms of dibenzoylmethane have been investigated via quantum chemistry and quantum crystallography methods to describe and explain a particular position of hydroxyl hydrogen atom in malondialdehyde quasi-ring of the chalcone.

A cocrystal of L-ascorbic acid with picolinic acid: the role of O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds and L-ascorbic acid con­formation in structure stabilization

A new cocrystal of L-ascorbic and picolinic acids is reported. The relationship between the con­formation of the L-ascorbic acid molecule and its effective charge in the new cocrystal, as well as in pure ascorbic acid and 12 previously documented L-ascorbic acid cocrystals, is discussed.

Pressure-induced Pb–Pb bonding and phase transition in Pb₂SnO₄

The structure of Pb₂SnO₄ is found to strongly distort on compression and a structural phase transition with a change of space group from Pbam to Pnam occurs at ∼11 GPa. Our complementary DFT-based calculations show that at ambient conditions, the channels in the structure host the stereochemically active Pb 6s² lone electron pairs which form bonds between the Pb²⁺ ions with increasing pressure.

The first bis­muth borate oxyiodide, Bi₄BO₇I: commensurate or incommensurate?

The first bis­muth borate oxyiodide, Bi₄BO₇I, is incommensurately modulated with q = 0.242 (3)c*. The wavevector is very close to the rational value of c*/4, yet refinement based on commensurate modulation faces serious problems indicating the incommensurate nature of the modulation.

Seven new metal–organic frameworks assembled from semi-rigid poly­car­box­ylate and auxiliary N-donor ligands: syntheses, structures and properties

Seven new metal–organic frameworks (MOFs) assembled from 3-(3,5-di­car­box­yl­phen­oxy)­phthalic acid (H₄L¹) and 4-(3,5-di­car­box­yl­phen­oxy)­phthalic acid (H₄L²) have been synthesized under similar conditions with transition-metal ions in the presence of auxiliary N-donor ligands. The various structures of the MOFs have been generated by adjusting the N-donor auxiliary ligands and the central metal ions. Their syntheses, 3D supramolecular structures, topological structures, structural comparison, fluorescence and magnetic properties are discussed in detail.

Charge density analysis of abiraterone acetate

Experimental charge density distribution of abiraterone acetate is reported. Intermolecular interactions in the crystals of abiraterone, abiraterone acetate and abiraterone complexes with cytochrome P450 binding pocket are compared.

Cation distribution in Cu₂ZnSnSe₄, Cu₂FeSnS₄ and Cu₂ZnSiSe₄ by multiple-edge anomalous diffraction

Multiple-Edge Anomalous Diffraction (MEAD) has been applied to various quaternary sulfosalts belonging to the adamantine compound family in order to validate the distribution of copper, zinc and iron cations in the structure. Application of this technique confirms established cation distribution in Cu₂ZnSnSe₄ (CZTSe) and Cu₂FeSnS₄ (CFTS), but in Cu₂ZnSiSe₄ (CZSiSe) the cation distribution is shown to adopt a highly ordered wurtz-kesterite structure type in contrast to the literature.

A new olanzapine cocrystal obtained from volatile deep eutectic solvents and determined by 3D electron diffraction

A new olanzapine–phenol cocrystal was discovered as an intermediate product during the crystallization of olanzapine from volatile deep eutectic solvents. The ability of 3D ED to investigate nanocrystalline intermediate forms paves the way for a thorough understanding of the crystallization pathways in pharmaceutical chemistry.

Correlation of the Madelung constant and I—M—I bonding angle with cohesive energy contributions in layered metal diiodides (MI₂) with CdI₂ (2H polytype) structure

It is demonstrated that the flatness parameter of layers, the Madelung constant and the bonding angle I—M—I are strictly correlated and increase in the same order: FeI₂ < PbI₂ < MnI₂ < CdI₂ < MgI₂ < CaI₂. With the increase of the Madelung constant and bonding angle I—M—I the relative contribution of the Coulomb energy to cohesive energy increases, whereas the relative contribution of the covalent energy decreases.

Ca-doped rare earth perovskite materials for tailored exsolution of metal nanoparticles

The ability of perovskite-type oxide materials to exsolve nanoparticles can be controlled by changing their elemental composition. This enables the precise and controlled preparation of catalyst materials with nanoparticles decorating the surfaces.

Single crystals of ferroelectric lithium niobate–tantalate LiNb_1–xTa_xO₃ solid solutions for high-temperature sensor and actuator applications

Ferroelectric LiNb_1–xTa_xO₃ crystals with various compositions were grown from the melt by the Czochralski method. The compositions, crystal unit-cell parameters and physical properties of the grown crystals including Curie temperature and velocity of surface acoustic waves were studied.

Two conformational polymorphs of 4-methyl­hippuric acid

A combination of resources – FT–IR, X-ray diffraction, PES, RMSD, Hirshfeld surface analysis and the Quantum Theory of Atoms in Molecules (QTAIM), and electron localization theories implemented in QTAIM, ELF and NCI – were used to study two conformational polymorphs of 4-methylhippuric acid obtained by solvent evaporation and mechanical grinding.

Distorted Te nets in the modulated crystal structures of RETe_1.94(1) (RE = La, Pr, Nd)

The incommensurately modulated crystal structures of RETe_1.94 (1) (RE = La, Pr, Nd) feature Te vacancies and different polytelluride fragments in planar chalcogenide layers.

Flux growth, structure refinement and Mössbauer studies of Fe_1–xGa_xBO₃ single crystals

High-quality Fe_1–xGa_xBO₃ single crystals with 0 ≤ x ≤ 1 were flux-grown and studied using energy-dispersive X-ray spectroscopy, X-ray diffraction and Mössbauer spectroscopy.

Structure and stability of γ₁-AuZn_2.1: a γ-brass-related complex phase in the Au–Zn System

The synthesis, crystal structure and stability of the γ-brass-related complex phase γ₁-AuZn_2.1 in the Au–Zn binary system are reported. The compound has been described as consisting of two main building units, i.e. a 38-atom modified Pierce cluster and an intergrown 19-atom double icosahedron.

Fine details of crystal structure and atomic vibrations in YbB₁₂ with a metal–insulator transition

The correlation between the characteristic changes in the structural parameters and physical properties of Kondo insulator YbB₁₂ in the temperature range of the metal–insulator transition has been studied for the first time.

Single crystal X-ray structure determination and temperature-dependent structural studies of the smectogenic compound 7OS5

Determination of an orthorhombic crystal structure in a solid phase of smectogenic compound 7OS5 (4-n-pentyl­phenyl-4′-n-heptyl­oxythio­benzoate) is reported. Polymorphism in the solid and liquid crystalline phases is investigated by complementary methods.

Crystal design by CH⋯N and N⋯N interactions: high-pressure structures of high-nitrogen-content azido-triazolopyridazines compounds

Two high-nitro­gen-content azido-triazolo pyridazines (C₅H₃N₇ and C₆H₅N₇) crystallize either as anhydrate or hydrated clathrate. High pressure changes the water content in the clathrate. Intermolecular contacts N⋯N are formed between the azide group only.

Fundamental aspects of symmetry and order parameter coupling for martensitic transition sequences in Heusler alloys. Erratum

Corrections are made to certain entries in Table 3 of the paper by Carpenter & Howard [(2018), Acta Cryst. B74, 560–573].

Natural Quasicrystals: The Solar System's Hidden Secrets