forthcoming articles

The program GraphT–T (V1.0Beta) has been developed to embed graphical representations of observed and hypothetical chains of (SiO₄)⁴⁻ tetrahedra into 2D and 3D Euclidean space.

Following the previous work [Biran & Gorfman (2024). Acta Cryst. A80, 112–128], all the possibilities for permissible (mismatch-free) walls between monoclinic domains of pseudocubic ferroelectric perovskites of M_C type are analyzed. The study yields analytical expressions for the orientation of such walls, the orientation relationship between the lattice vectors and for the separation between Bragg peaks diffracted from matched domains.

It is shown that all possible topologically distinct chain graphs of tetrahedra may be embedded into 3D Euclidean space. In minerals, separations between linked T cations are 3.06 (15) Å and between unlinked T cations are >3.71 Å, and these distances constrain the ability of embedded chain graphs to occur as structural entities in crystals. Software (GraphT-T) allows this embedding to be tested for stereochemical viability.

The essay introduces a novel dual-detection fluorescent sensing platform, Eu@nZCP, for highly selective sensing of mercury (Hg) and L-Cysteine (L-Cys) in aqueous media. The platform is based on a new nanoscale Zn^II coordination polymer (nZCP) synthesized using ultrasound irradiations, incorporating Eu³⁺ ions into its host lattice (Eu@nZCP). The analog single crystal (ZCP) was also prepared and using SXRD, its structure determined as a 2D porous CP with distinctive 6³ network.

Density-functional calculations using numerical atomic orbitals and the exchange-hole dipole moment dispersion model were applied to the energy ranking stage of the [for 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 novel ternary oxynitride SnGe₄N₄O₄ has been synthesized under high-pressure high-temperature conditions in a large-volume press. Its crystal structure (P6₃mc) and the crystal structure of a 6R polytype (R3m) were determined by three-dimensional electron diffraction from submicrometer-sized crystals.

The presence of three unique trimeric supramolecular motifs in the crystal structures of dihalogenated 1,2,4-triazole derivatives is explored.

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 diethyl N,N′-(1,3-phenyl­ene)dicarbamate–theophylline (1–TEO) com­plex was obtained by mechanochemistry involving the conformational change of one of the ethyl carbamate groups of 1 from the endo conformation to the exo conformation to allow the formation of the inter­molecular inter­actions.

Crystallization of 3,3′,5,5′-tetra­nitro-4,4′-bi­pyrazole obeys Ostwald's rule of stages and features the emergence of metastable highly hydrated phases prior to the formation of the stable monohydrate.

A new polymorphic form of the caffeine–citric acid cocrystal, solved by powder X-ray diffraction thanks to synchrotron experiments, was com­pared with the already known forms. An analysis of the hydrogen bonding indicates that the cocrystal obtained here is less stable than the co­crystals already identified in the literature.

The crystal structure of the cubic ternary germanide Mg_5.57Ni₁₆Ge_7.43 has been determined by single-crystal X-ray diffraction. The structure type represents the structure family based on the Th₆Mn₂₃-type and Mg₆Cu₁₆Si₇. A new type of polyhedron, i.e. a penta­conta­tetra­hedron, which is based on triangular, tetra­gonal and penta­gonal faces, is described. Electronic structure and hydrogenation properties are discussed.

This review covers the symptoms of radiation damage in macromolecular crystallography, how to avoid accruing radiation damage during data collection, and how to identify and correct for radiation damage artefacts in a solved structure.

Through the analysis of more than 115 000 metal-binding sites in metalloproteins, experimentalists are offered useful reference data that improve the understanding of metal-binding interactions and protein coordination. Carboxylate coordination, which is common for a variety of metals, is especially highlighted.

Very large high-quality crystals of a new member of the family of double nitrates, namely, [La(NO₃)₆]₂[Ni(H₂O)₆]₃·6H₂O, were crystallized in large amounts. The structure was determined via single-crystal X-ray diffraction to high resolution. Extensive structural information, including hydrogen-bonding details, was obtained at the same time.

In the crystal, mol­ecules are linked by C—H⋯π inter­actions, forming ribbons along the a axis. Inter­molecular C—H⋯O hydrogen bonds connect these ribbons to each other, forming layers parallel to the (01) plane. The mol­ecular packing is strengthened by van der Waals inter­actions between the layers.

The title com­pound exhibits the typical rhomboid-like four-membered Sn–OH ring found in all dimeric mol­ecules of monoorganotin(IV)–dihalide–hydroxides, with acute bond angles at the Sn atom, obtuse bond angles at O atoms and shorter Sn—O bond lengths trans to the ethyl groups.

The two independent mol­ecules of C₂₃H₂₁BrN₄O are closely similar and roughly planar except for the isopropyl groups. They are connected by hydrogen bonds of the types N_amide—H⋯N≡C, H_phen­yl⋯O=C and H_phen­yl⋯Br.

The structures of fourteen halochalcogenido­phospho­nium tetra­halogenidoaurates(III) of general formula [R¹_3-nR²_nPEX][AuX₄] (R¹ = t-butyl; R² = i-propyl; n = 0 to 3; E = S or Se; X = Cl or Br) are presented and compared.

The article discusses the phase contrast effect and compare two simulation methods based on different theoretical frameworks. It demonstrates the ability to reproduce the phase effect in experimental data, using a well-known simulation framework McStas.

iModel is an innovative 3D crystal structure visualization program that allows users to manipulate and customize models. Developed using LabVIEW and Python, it is a potentially powerful tool for crystal structure visualization.

Bragg Spot Finder (BSF) is a UNet-based spotfinder with image preprocessing, a UNet segmentation backbone, and post-processing that includes artifact removal and Watershed segmentation. BSF is supported by the Bragg Spot Detection (BSD) benchmark image dataset containing more than 300 images with more than 66 000 spots.

A novel high-efficiency 2D position-sensitive WLSF ZnS:Ag/⁶LiF scintillator detector was developed at ISIS for single-crystal diffraction applications. More than a factor three improvement in efficiency was achieved with this detector compared to clear-fibre scintillator detectors. Software routines for further optimisations in position sensitivity and uniformity have been implemented for this type of detectors. This new high-efficiency double-layer WLSF detector concept enables upgrades to the ISIS instrument suite and extends the facility's scientific capabilities. Sketch of the double scintillator-fibre layer arrangement. A single layer consists of two orthogonal fibre planes (1 mm 3 mm pitch) sandwiched between scintillator sheets (450 µm thick) with reflective foils (50 µm thick) and a 5 mm B₄C plate to reduce neutron background.

The program VUE analyses the distribution of the 2D projections in cryoEM and presents this information in a quantitatively exact manner by maps and other diagrams.

This report describes an `order–disorder' transition in the recently discovered K₂Ca₃(CO₃)₄ material and the disordered β modification with an unusual K–Ca isomorphism in cation sites. The appearance of mixed K/Ca sites, in turn, causes strong orientational disorder of anions and the emergence of an inversion center (the ordered α modification is non-centrosymmetric).

A computer program called Multifitting, which was developed to model the optical properties of multilayer films over a wide range of wavelengths, is described here. The key features of Multifitting are the ability to work simultaneously with an arbitrary number of reflectometric and scatterometric experimental curves, and an ergonomic graphical user interface that is designed for intensive daily use in the characterization of thin films.

The disequilibrium Sn content in Pb inclusions present in ancient (Sn,Cu)-bronze samples may in principle be used for authentication purposes. The present article explores the applicability of the method, based on the precise diffraction measurement of the Pb lattice parameter.

The possible energies of different active adsorption sites of nanostructured Mo-doped symmetric reduced graphene (rG), Mo-decorated graphene, asymmetric reduced graphene and reduced graphene oxide (rGO) have been calculated using density functional theory (DFT). Covalent interactions between Mo and rG/rGO structures result in adsorption bonding, enhancing electrical conductivity and making them ideal for eliminating pollutants.

The recent upgrade of the infrared beamline at the BESSY II storage ring made possible improved characterization of molecules and materials at different length and time scales. The new nano-spectroscopy endstation based on a scattering-type scanning optical microscope enables infrared imaging and spectroscopy with a spatial resolution better than 30 nm.

This study showcases the potential of the PINK beamline for advancing research in the field of non-resonant X-ray emission spectroscopy in the tender X-ray energy range from 2.1 keV to 9.5 keV.

The first crystal structure of phytoplasma immunodominant membrane protein is reported and structural analysis revealed its potential for actin binding.

A structural analysis of several metal-ion binders that inhibit viral endonucleases is performed.

This topic review summarizes structures of chaperones complexed with MHC-I, the structural principles that govern peptide exchange and the mechanism in antigen presentation.

The human peptidylarginine deiminase type VI (PAD6) is essential in oocyte and embryonic development as a component of the supramolecular assemblies called cytoplasmic lattices. The crystal structure presented here suggests PAD6 assembles as a dimer resembling other PADs, albeit with compromised abilities to bind Ca²⁺ and substrates. This aligns with existing in vitro data which indicate an enzymatically inactive isoform of PAD.

A kinetics-informed neural-network method (KINNTREX) is designed to analyze a time series of difference maps from a time-resolved X-ray crystallographic experiment.

The crystal structure model of germacrone type II determined from single-crystal X-ray data is compared with that of a previous synchrotron X-ray powder study

The title compound features bifurcated template-to-framework N—H⋯(O,O) hydrogen bonds.

The title complex exhibits a distorted octa­hedral geometry about the metal centre, which coordinates two tridentate ligands that are perpendicular to each other.

The structure of bis­[2,3-bis­(thio­phen-2-yl)pyrido[3,4-b]pyrazine]­silver(I) perchlorate methanol disolvate is monoclinic. The Ag atom coordinates pyrido N atoms and is two-coordinate; however, the Ag atom has nearby O atoms that can be assumed to be weakly bonding – one from the perchlorate anion and one from the methanol solvate. One of the thienyl groups of a 2,3-bis­(thio­phen-2-yl)pyrido[3,4-b]pyrazine is flipped disordered and was refined to occupancies of 68.4 (6) and 31.6 (6)%.

The title compound crystallizes in the non-centrosymmetric ortho­rhom­bic space group Fdd2, with 16 mol­ecules in the unit cell. In the crystal, aromatic π–π stacking distance and short C—H⋯O contacts are observed.