{"title":"XRDplayground: a Python-based educational tool for interactive learning of powder X-ray diffraction crystallography","authors":"Flávia Regina Estrada, Antonio Malfatti-Gasperini","doi":"10.1107/S1600576725001220","DOIUrl":"https://doi.org/10.1107/S1600576725001220","url":null,"abstract":"<p>One of the barriers to learning crystallography through the powder X-ray diffraction (PXRD) technique is the understanding and visualization of the crystal structure and its effects on the diffraction pattern. To enhance learning through visualization, we present <i>XRDplayground</i>, an open-source software developed in Python that can simultaneously simulate the unit cell and its PXRD pattern. It features a graphical user interface where all the structural parameters of the crystal, such as lattice parameters and atomic positions inside the unit cell, are adjustable via sliders. The PXRD pattern is simulated by taking into consideration the X-ray energy and the crystallite size using Scherer's equation. <i>XRDplayground</i> is an educational tool to make PXRD crystallography more engaging and enhance learning and understanding of the concepts rather than mathematical treatment and/or superficial memorization.</p>","PeriodicalId":48737,"journal":{"name":"Journal of Applied Crystallography","volume":"58 2","pages":"609-614"},"PeriodicalIF":5.2,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143741179","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Dries Vandenabeele, Nikolaus Doppelhammer, Martin Rosenthal, Wauter Wangermez, Bernhard Jakoby, Christine Kirschhock, Eric Breynaert
{"title":"A simple and robust high-pressure cell for transmission X-ray investigation","authors":"Dries Vandenabeele, Nikolaus Doppelhammer, Martin Rosenthal, Wauter Wangermez, Bernhard Jakoby, Christine Kirschhock, Eric Breynaert","doi":"10.1107/S1600576725000226","DOIUrl":"https://doi.org/10.1107/S1600576725000226","url":null,"abstract":"<p>A simple and robust high-pressure cell designed for <i>in situ</i> transmission X-ray crystallization studies is presented. The performance of the cell for <i>in situ</i> small/wide-angle X-ray scattering experiments and microscopy imaging is demonstrated for zeolite crystallization from highly alkaline hydrated silicate ionic liquids at 500 K and 150 bar N<sub>2</sub> pressure. The simple design in combination with commercial finger-tight connections allows for convenient sample loading of powders, liquids and gases. The cell can be used in dead-end or flow-through mode and can be pressurized with gases or liquids via standard high-performance liquid chromatography capillary tubing. The capillaries are easily cleaned or replaced. The wetted parts are polyether ether ketone and sapphire, which are resistant to many corrosive substances, thus enabling <i>in situ</i> characterization under challenging conditions.</p>","PeriodicalId":48737,"journal":{"name":"Journal of Applied Crystallography","volume":"58 2","pages":"392-397"},"PeriodicalIF":5.2,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143741178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rebecca Scatena, Zachary E. Manson, Danielle Y. Villa, Jamie L. Manson, David R. Allan, Paul A. Goddard, Roger D. Johnson
{"title":"Electron-density analysis of halide…halide through-space magnetic exchange","authors":"Rebecca Scatena, Zachary E. Manson, Danielle Y. Villa, Jamie L. Manson, David R. Allan, Paul A. Goddard, Roger D. Johnson","doi":"10.1107/S1600576725000536","DOIUrl":"https://doi.org/10.1107/S1600576725000536","url":null,"abstract":"<p>We present a combined experimental and density functional theory study that characterizes the charge and spin density in Ni<i>X</i><sub>2</sub>(3,5-lutidine)<sub>4</sub> (<i>X</i> = Cl, Br and I). In this material, magnetic exchange interactions occur via Ni<sup>2+</sup>–halide…halide–Ni<sup>2+</sup> pathways, forming one-dimensional chains. We find evidence for weak halide…halide covalency in the iodine system, which is greatly reduced when <i>X</i> = Br and is absent for <i>X</i> = Cl; this is consistent with the reported `switching-on' of magnetic exchange in the larger-halide cases. Our results are benchmarked against density functional theory calculations on [NiHF<sub>2</sub>(pyrazine)<sub>2</sub>]SbF<sub>6</sub>, in which the primary magnetic exchange is mediated by F–H–F bridging ligands. This comparison indicates that, despite the largely depleted charge density found at the centre of halide…halide bonds, these through-space interactions can support strong magnetic exchange gated by weak covalency and enhanced by significant electron density overlapping that of the transition metal centres.</p>","PeriodicalId":48737,"journal":{"name":"Journal of Applied Crystallography","volume":"58 2","pages":"363-373"},"PeriodicalIF":5.2,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143741181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Brandon Schwendeman, Bennett C. Larson, Michael J. Simmonds, Thomas Schwarz-Selinger, Sabine Faulhaber, Matthew J. Baldwin, George R. Tynan
{"title":"Integral X-ray diffuse scattering for studying irradiation-induced dislocation loops in single crystals","authors":"Brandon Schwendeman, Bennett C. Larson, Michael J. Simmonds, Thomas Schwarz-Selinger, Sabine Faulhaber, Matthew J. Baldwin, George R. Tynan","doi":"10.1107/S1600576724012202","DOIUrl":"https://doi.org/10.1107/S1600576724012202","url":null,"abstract":"<p>Numerical diffuse scattering cross-section calculations are used to establish a rigorous basis for determining the concentration and size distribution of dislocation loops in irradiated single crystals from integral X-ray diffuse scattering (XRDS) measurements. Differential XRDS intensities for prismatic {111} type dislocation loops are numerically calculated as a function of loop radius <i>R</i> and wavevectors <b>q</b> relative to Bragg reflections in tungsten. The results show the well known 1/<i>q</i><sup>2</sup> Huang scattering form at small <i>q</i> that transitions to a ∼1/<i>q</i><sup>4</sup> dependence associated with the Stokes–Wilson approximation for <i>q</i> ≳ 1/<i>R</i>. More importantly, they show further that the 1/<i>q</i><sup>4</sup> falloff is not the asymptotic large-<i>q</i> form of the diffuse scattering for small loops (<i>R</i> < 200 Å) as has often been assumed. Rather, for loop sizes as small as <i>R</i> ≃ 5 Å with strong curvature, the calculations show definitively that the scattering transitions to a robust 1/<i>q</i><sup>5</sup> falloff at larger <i>q</i> that arises due to the local strains near the dislocation core defining the circumference of the dislocation loops. The presence of this 1/<i>q</i><sup>5</sup> asymptotic form for both small and large loops is experimentally confirmed using an integral XRDS measurement around the 110 reflection on self-ion-irradiated tungsten combined with numerically calculated integral XRDS cross-sections. Accordingly, the historical two-region theoretical treatment of the cross-sections for integral XRDS is extended to a three-region model that has direct sensitivity to the (first-moment) dislocation line lengths of dislocation loops. These developments enable the use of both numerical and analytically modeled cross-sections to make accurate integral XRDS determinations of dislocation loop sizes and concentrations using modest-intensity laboratory X-ray sources.</p>","PeriodicalId":48737,"journal":{"name":"Journal of Applied Crystallography","volume":"58 2","pages":"302-320"},"PeriodicalIF":5.2,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143741281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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