Pushing crystallography's frontiers through quantum mechanics

Yu & Gillet [Acta Cryst. (2025), B81, 168–180] extend quantum crystallography (QCr) by integrating real-space (1-RDM) and phase-space (Wigner function) representations, combining elastic and inelastic X-ray scattering to experimentally probe electron behavior in crystals. Their reconstruction of the quantum properties of a urea crystal bridges quantum chemistry and crystallography in a novel and imaginative way.

The chemical theory of valence

Relaxing the restriction that valence can only adopt integer values removes the distinction between ionic and covalent bonds, resulting in a simple and powerful valence theory that is able to predict the structures and chemical properties of both organic and inorganic compounds.

Intrusion of quantum crystallography into classical lands

One hundred years after the quantum theory established position and momentum as incompatible quantities, quantum crystallography offers a way to visualize electron phase space behaviour in crystals.

Computational analysis tools for magnetic structures in the Bilbao Crystallographic Server

Summary of the tools provided by the Bilbao Crystallographic Server for the analysis and determination of magnetic structures.

Electric charge and salting in/out effects on glucagon's dipole moments and polarizabilities using the GruPol database

This work explores the prediction of glucagon's dipole moments and polarizabilities using the GruPol database, incorporating ionic effects and solvation conditions. The results highlight the influence of high ionic concentrations on the protein's electrical properties, demonstrating good agreement with quantum mechanical benchmarks.

Structural and magnetic properties of β-Li₂IrO₃ after grazing-angle focused ion beam thinning

A minimally invasive use of a focused ion beam at grazing incidence can reduce the size of bulk crystals without jeopardizing the structural and electronic order parameters.

Computation screening for incorrectly determined cocrystal structures

Computational salt–cocrystal differentiation, based on density functional theory improved by up-to-date functionals rSCAN and r2SCAN, has been tested for 404 structures. Several problematic structures have been redetermined.

Is it possible to obtain a plausible experimental electronic structure without collecting high-order diffraction data?

Experimental electronic structure comparison of the multipole refinement with full dataset and the refinement using the low-order dataset with NospherA2 geometry.

A new crystal phase of calcium stannate CaSn₂O₄(OH)₂ and its physico-chemical properties

At 623 K, the thermovapour treatment of calcium and tin oxides leads to the formation of the previously unknown CaSn₂O₄(OH)₂ lamellar crystals. This phase is stable up to 973 K and has high catalytic activity and selectivity to C₆₊ products in the aldol condensation of acetone.

Disorder- and magnetism-driven structural changes in Sm₂Mn_1–xGa_6–yGe_y

High-resolution single-crystal X-ray diffraction experiments were performed for Sm₂Mn_1–xGa_6–yGe_y over a wide temperature range (180–430 K). The experiments revealed significant structural changes that are caused by structural disorder and magnetic ordering.

Electron density and elastic properties of crystalline [Co(NH₃)₅NO₂]ClNO₃: a quantum crystallography study

Intra- and intermolecular interactions and elastic properties of crystalline [Co(NH₃)₅NO₂]ClNO₃ are investigated.

Looking at high-pressure electrides through the lens of quantum crystallography: the case of simple cubic calcium

The electron density and bonding nature of simple cubic Ca up to a phase 40 GPa is analyzed using theoretical quantum crystallography methods. The analysis is concerned with the electronic structure, pressure-induced electronic transitions, multi-center bond formation, topology of the electron density and atomic electronegativities.

Qu­antitative crystal structure analysis in tri­fluoro­methyl- and cyano-substituted N-phenyl­benzamides

The role of weak intermolecular interactions [C—H⋯N≡C, C—H⋯F—C(sp³) and C(sp³)—F⋯F—C(sp³)] in the presence or absence of strong N—H⋯O hydrogen bonds, in a series of CN and CF₃ substituted crystalline N-phenyl benzamides is studied. Mapping of the crystal structure landscape for N-phenyl benzamide was performed by analysis of the crystal structures of the substituted compounds.

Strain distribution in GaN/AlN superlattices grown on AlN/sapphire templates: comparison of X-ray diffraction and photoluminescence studies

Strain in GaN/AlN superlattices decreases with increasing well/barrier thickness. The optimum superlattice interface quality is achieved for a structure with a barrier thickness of 3 nm. The quantum-confined Stark effect causes red-shift in photoluminescence spectra, confirmed by DFT calculations.

Analytical description of nanowires. III. Regular cross sections for Wurtzite structures. Corrigendum

Corrections to the article by König & Smith [Acta Cryst. (2022), B78, 665–677] are given.