The high-resolution powder diffraction beamline at ESRF (ID22), built with a dual-undulator source on the 6 GeV storage ring, combines a wide continuous range of incident energy (6–80 keV) with high brightness, offering the possibility to carry out high-flux high-resolution powder diffraction measurements. In routine operation, a bank of nine scintillation detectors is scanned vertically to measure the diffracted intensity versus 2θ, each detector being preceded by an Si 111 analyser crystal. Although the current detector system has operated successfully for the past 20 years, recent developments in detector technology could be exploited to improve the overall performance. With this in mind, as a test, a two-dimensional Pilatus3 X CdTe 300 K-W pixel detector has been mounted on the arm of the diffractometer, replacing the nine scintillator detectors. At each nominal 2θ value, a two-dimensional image is recorded showing nine distinct regions corresponding to the diffraction signals passing via each of the analyser crystals. This arrangement offers new flexibility in terms of data handling and processing, with the possibility to optimize both peak shape and statistics, to remove parasitic effects, and to gain spatial resolution information. Combining the high efficiency of a hybrid photon-counting area detector with the high angular resolution given by analyser crystals is an effective approach to improving the overall performance of high-resolution powder diffraction.

Two novel yttrium nitrides, YN₆ and Y₂N₁₁, were synthesized by direct reaction between yttrium and nitrogen at 100 GPa and 3000 K in a laser‐heated diamond anvil cell. High‐pressure synchrotron single‐crystal X‐ray diffraction revealed that the crystal structures of YN₆ and Y₂N₁₁ feature a unique organization of nitrogen atoms—a previously unknown anionic N₁₈ macrocycle and a polynitrogen double helix, respectively. Density functional theory calculations, confirming the dynamical stability of the YN₆ and Y₂N₁₁ compounds, show an anion‐driven metallicity, explaining the unusual bond orders in the polynitrogen units. As the charge state of the polynitrogen double helix in Y₂N₁₁ is different from that previously found in Hf₂N₁₁ and because N₁₈ macrocycles have never been predicted or observed, their discovery significantly extends the chemistry of polynitrides.

The structural origin of the remarkable performance of the metal–organic framework Fe ₂ (BPEB) ₃ as a CO ₂ adsorbent (40.5% of the host weight at 298 K and 10 bar) was investigated by combining advanced experimental and computational tools.

The mechanism of hydration of calcium sulfate hemihydrate (CaSO₄·0.5H₂O) to form gypsum (CaSO₄·2H₂O) was studied by combining scanning 3D X-ray diffraction (s3DXRD) and phase contrast tomography (PCT) to determine in situ the spatial and crystallographic relationship between these two phases. From s3DXRD measurements, the crystallographic structure, orientation and position of the crystalline grains in the sample during the hydration reaction were obtained, while the PCT reconstructions allowed visualization of the 3D shapes of the crystals during the reaction. This multi-scale study unfolds structural and morphological evidence of the dissolution–precipitation process of the gypsum plaster system, providing insights into the reactivity of specific crystallographic facets of the hemihydrate. In this work, epitaxial growth of gypsum crystals on the hemihydrate grains was not observed.