Acta crystallographica Section B, Structural science, crystal engineering and materials最新文献

{"title":"Magnetic structure determination of multiple phases in the multiferroic candidate GdCrO₃.","authors":"Pascal Manuel, Dmitry Khalyavin, Fabio Orlandi, Laurent Chapon, Wang Xueyun, Tae Hwan Jang, Eun Sang Choi, Sang Wook Cheong","doi":"10.1107/S2052520625001921","DOIUrl":"10.1107/S2052520625001921","url":null,"abstract":"<p><p>Due to their potential applications in low-power consumption and/or multistate memory devices, multiferroic materials have attracted a lot of attention in the condensed matter community. As part of the effort to identify new multiferroic compounds, perovskite-based GdCrO₃ was studied in both bulk and thin film samples. A strong enhancement of the capacitance in a field suggested ferroelectric behaviour but significant leakage and no well developed P-E hysteresis loops were observed. Measurements clearly indicate the existence of a polar phase but only below 2 K (likely connected to Gd ordering). Here the determination of the magnetic structure through neutron diffraction collected on an isotopic ¹⁶⁰GdCrO₃ sample at the WISH diffractometer at ISIS is reported. The presence of three successive magnetic phases as a function of temperature (commensurate, spin re-orientation and incommensurate phases once the Gd order), previously only seen by magnetization, is confirmed. Using the most recent guidelines for reporting the determined structures, we highlight the benefits of using such nomenclature for discussing physical properties and consider possible mechanisms and couplings that led this seemingly rather isotropic system to display the complex structures observed.</p>","PeriodicalId":7320,"journal":{"name":"Acta crystallographica Section B, Structural science, crystal engineering and materials","volume":" ","pages":"293-301"},"PeriodicalIF":1.3,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12147934/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143952055","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cs₄Ca[Si₈O₁₉]: a new mixed tetrahedral-octahedral oxosilicate, its topological features and comparison with other interrupted framework silicates.","authors":"Volker Kahlenberg","doi":"10.1107/S2052520625002537","DOIUrl":"10.1107/S2052520625002537","url":null,"abstract":"<p><p>Single crystals of a previously unknown caesium calcium silicate with the composition Ca₄Ca[Si₈O₁₉] have been obtained during a systematic study of the phase relations and compound formation in the system Cs₂O-CaO-SiO₂. Structure determination was based on a single-crystal diffraction data set recorded at 288 (2) K. The compound crystallizes in the monoclinic space group P2₁/n and has the following basic crystallographic parameters: a = 7.1670 (6) Å, b = 12.0884 (10) Å, c = 12.4019 (10) Å, β = 90.044 (8)°, V = 1074.47 (15) ų, Z = 2. The crystal structure was solved by direct methods. The sample showed twinning by pseudo-merohedry, which was accounted for in the subsequent least-squares refinements resulting in a residual of R1 = 0.036 for 1962 independent observed reflections and 149 parameters. The crystal structure of Cs₄Ca[Si₈O₁₉] belongs to the group of interrupted framework silicates, in which the [SiO₄] tetrahedra are linked in a three-dimensional network consisting of Q⁴ and Q³ groups in a 1:3 ratio. The linear backbones of the framework can be described as loop-branched dreier single chains. These ribbons are parallel to [100], and the translation period of about 7.2 Å along this axis reflects the periodicity of the chains. By sharing common corners, the condensation of these chains along the [001] direction leads to the formation of layers that are parallel to (010) and contain three- and nine-membered rings of tetrahedra. Alternatively, the crystal structure can be described as a mixed tetrahedral-octahedral framework between [SiO₄] tetrahedra and [CaO₆] octahedra containing cavities accommodating the caesium ions coordinated by seven and eight oxygen ligands, respectively. A detailed topological analysis of the mixed framework based on natural tiles is presented. Indeed, the net can be constructed from a total of only two different cages (tiles) having the following face symbols: [4³] and [3⁴.4⁶.6².7⁸]. A comparison with related silicates containing [Si₈O₁₉] anions and already classified as well as hitherto unclassified interrupted frameworks is presented. Finally, the thermal expansion tensor has been determined in the temperature interval between 193 K and 288 (2) K.</p>","PeriodicalId":7320,"journal":{"name":"Acta crystallographica Section B, Structural science, crystal engineering and materials","volume":" ","pages":"325-336"},"PeriodicalIF":1.3,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12147939/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143952142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magnetic structure determination and refinement using FullProf.","authors":"Juan Rodriguez-Carvajal, Javier Gonzalez-Platas, Nebil A Katcho","doi":"10.1107/S2052520625003944","DOIUrl":"10.1107/S2052520625003944","url":null,"abstract":"<p><p>The study of magnetic structures from a crystallographic perspective remains a niche field, largely confined to physical crystallography and microscopic magnetism. Unlike general or superspace crystallography, magnetic structure analysis lacks standardization, primarily due to the small research community and the reliance on specialized experimental techniques like neutron diffraction. However, emerging topics in condensed matter physics, such as topological materials, multiferroics, and skyrmions, have heightened the importance of understanding magnetic ordering. As a result, the analysis of magnetic neutron scattering data is becoming increasingly relevant, requiring unified methodologies. Since 2011, the IUCr Commission on Magnetic Structures has been working to improve the situation. This paper reviews the most commonly used methods for describing magnetic structures and highlights the capabilities of the FullProf Suite for analysing magnetic neutron diffraction data.</p>","PeriodicalId":7320,"journal":{"name":"Acta crystallographica Section B, Structural science, crystal engineering and materials","volume":" ","pages":"302-317"},"PeriodicalIF":1.3,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12147938/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144232878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shifting and tilting towards enhanced piezoelectricity in high-temperature ceramics: an average structure study of (1 - x)BiFe_2/8Ti_3/8Mg_3/8O₃-xPbTiO₃ through X-ray and neutron diffraction.","authors":"Brooke N Richtik, Alicia Manjón-Sanz, Michelle Dolgos","doi":"10.1107/S2052520625002781","DOIUrl":"10.1107/S2052520625002781","url":null,"abstract":"<p><p>A comprehensive report is provided of the average structure of a high Curie temperature ferroelectric ceramic, (1 - x)BiFe_2/8Ti_3/8Mg_3/8O₃-xPbTiO₃ (BFTM-xPT) when x = 0.25-0.375 at room temperature. Both neutron and synchrotron X-ray powder diffraction data were collected and combined Rietveld refinements were completed. These data revealed that, of the compositions studied, BFTM-xPT crystallizes as mixed phase material. At x = 0.25-0.275, the average structure of each phase is best described by space groups R3c and Cc. At 0.30 ≥ x ≥ 0.35, a morphotropic phase boundary is present and is best modelled by space groups P4mm and Cc, where space group Cc is the dominant phase. As the concentration of PbTiO₃ increases, the amount of octahedral tilting decreases and x = 0.375 exhibits a loss of octahedral tilting and crystallizes in space groups P4mm and Cm. An updated phase diagram at room temperature of this novel system is given and structural intricacies responsible for its piezoelectric properties are revealed.</p>","PeriodicalId":7320,"journal":{"name":"Acta crystallographica Section B, Structural science, crystal engineering and materials","volume":" ","pages":"337-349"},"PeriodicalIF":1.3,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143956069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of the transition metal on the structure and order-disorder phase transition in layered hybrid metal halides (CH₃CH₂NH₃)₂[MCl₄] (M = Mn and Co).","authors":"Shatakshi S Jakhi, Meenal Dhanetwal, V Raghavendra Reddy, Venkatesha R Hathwar","doi":"10.1107/S2052520625002719","DOIUrl":"10.1107/S2052520625002719","url":null,"abstract":"<p><p>Layered hybrid organic-inorganic metal halides (CH₃CH₂NH₃)₂[MnCl₄] and (CH₃CH₂NH₃)₂[CoCl₄] were synthesized by the slow evaporation method to understand the relationship between the crystal structure and order-disorder phase transition. Calorimetric data and crystal structure determination across the phase transition temperature establish the order-disorder phase transition. (CH₃CH₂NH₃)₂[MnCl₄] undergoes the reversible structural phase transition from tetragonal I4/mmm to orthorhombic Pbca at 212/222 K (cooling/heating), whereas (CH₃CH₂NH₃)₂CoCl₄ demonstrates the phase transition at 220/239 K from orthorhombic Pnma to orthorhombic P2₁2₁2₁. Both compounds are characterized by disordered ethyl ammonium cations in the structure above the phase transition temperature, whereas they become ordered cations at temperatures below the phase transition. Dielectric results further support the observed structural phase transitions. Additionally, magnetic measurements show canted antiferromagnetic characteristics for (CH₃CH₂NH₃)₂[MnCl₄] and paramagnetic behaviour is observed for (CH₃CH₂NH₃)₂[CoCl₄]. The structural differences, the role of intermolecular interactions and the effect of transition metals on the phase transition were evaluated using Hirshfeld surface analysis and the topological properties of electron density distributions. An accurate description of the structure and intermolecular interactions is crucial for understanding the physical properties and designing multifunctional hybrid organic-inorganic metal halide perovskites.</p>","PeriodicalId":7320,"journal":{"name":"Acta crystallographica Section B, Structural science, crystal engineering and materials","volume":" ","pages":"363-372"},"PeriodicalIF":1.3,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144155404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multipolar model and Hirshfeld atom refinement of tetraaquabis(hydrogenmaleato)iron(II).","authors":"Hellen Ferreira Guimarães, Bernardo Lages Rodrigues","doi":"10.1107/S2052520625003403","DOIUrl":"10.1107/S2052520625003403","url":null,"abstract":"<p><p>A high-resolution charge density study using the Hansen-Coppens multipolar model was performed on tetraaquabis(hydrogenmaleato)iron(II). The experimental electron density was subjected to Bader's topological analysis. Hirshfeld atom refinement and topological analysis of the molecular wavefunction were also conducted. A comparison of the properties obtained under different resolution and acquisition conditions are presented. The performance of these models is evaluated in terms of their ability to achieve bond lengths close to those from neutron diffraction, provide accurate anisotropic displacement parameters and model electron densities precisely, and to determine atomic charges under different experimental and modeling conditions. The structure presents a short intramolecular hydrogen bond, which is found to have a distinct character compared to other interactions, as the hydrogen interacts covalently with two oxygen atoms. Different models were evaluated, each outperforming the others in specific aspects. Overall, the analysis of these models provide deeper insights into electron density distribution and the nature of the interactions present in the structure.</p>","PeriodicalId":7320,"journal":{"name":"Acta crystallographica Section B, Structural science, crystal engineering and materials","volume":" ","pages":"350-362"},"PeriodicalIF":1.3,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12147936/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143960843","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unravelling the complexity of co-existing phases in piezoelectrics.","authors":"Brendan J Kennedy","doi":"10.1107/S2052520625004974","DOIUrl":"10.1107/S2052520625004974","url":null,"abstract":"<p><p>The strategy used by Richtik et al. [(2025), Acta Cryst. B81, 337-349] is a textbook example of how to address the complex crystallinity in multiphase ferroelectric ceramics.</p>","PeriodicalId":7320,"journal":{"name":"Acta crystallographica Section B, Structural science, crystal engineering and materials","volume":" ","pages":"291-292"},"PeriodicalIF":1.3,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144232879","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The varying temperature- and pressure-induced phase transition pathways in hybrid improper ferroelectric Sr₃Sn₂O₇.","authors":"Evie Ladbrook, Jeremiah P Tidey, Fei Ting Huang, Sang Wook Cheong, Dominik Daisenberger, Mark R Warren, Mark S Senn","doi":"10.1107/S2052520625002306","DOIUrl":"10.1107/S2052520625002306","url":null,"abstract":"<p><p>A variable-temperature and pressure single-crystal diffraction study of hybrid improper ferroelectric Sr₃Sn₂O₇ is reported. In combination with symmetry analysis, we reveal that the application of pressure and temperature induce distinct phase transition pathways, driven by a differing response of the octahedral rotations to these stimuli. Contrary to what has been previously predicted, we observe the ferroelectric to paraelectric phase transition between 10.17(18) and 12.13(14) GPa, meaning the hybrid improper ferroelectric phase remains stable to significantly higher pressures than expected.</p>","PeriodicalId":7320,"journal":{"name":"Acta crystallographica Section B, Structural science, crystal engineering and materials","volume":" ","pages":"318-324"},"PeriodicalIF":1.3,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12147935/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143959223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modulation of the modulated magnetic structure of an Ho i-MAX phase described by a magnetic (3+2)-dimensional superspace group. Corrigendum.","authors":"Claire V Colin, Quanzheng Tao, Christine Opagiste, Rafik Ballou, Johanna Rosen, Thierry Ouisse, Václav Petříček","doi":"10.1107/S2052520625003361","DOIUrl":"10.1107/S2052520625003361","url":null,"abstract":"<p><p>The name of one of the authors in the article by Colin et al. [Acta Cryst. (2025), B81, 37-46] is corrected.</p>","PeriodicalId":7320,"journal":{"name":"Acta crystallographica Section B, Structural science, crystal engineering and materials","volume":" ","pages":"375"},"PeriodicalIF":1.3,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12147937/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143952639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Computation screening for incorrectly determined cocrystal structures.","authors":"Simona Chalupná, Michal Hušák, Jan Čejka, František Fňukal, Jiří Klimeš","doi":"10.1107/S205252062500068X","DOIUrl":"10.1107/S205252062500068X","url":null,"abstract":"<p><p>Pharmaceutical solid forms, like salts and cocrystals, play a crucial role in drug formulation. Despite differing mainly by a single hydrogen atom, the regulatory requirements set by the US Food and Drug Administration for these forms vary significantly. We previously developed a DFT-based computational method to distinguish salts from cocrystals. This method, validated on 95 structures, performed well for systems where hydrogen bonds were longer than 2.613 (16) Å. Here, benefits of the rSCAN functional over the PBE functional are discussed. We expand the dataset to 404 cocrystal models. Analysis confirms that 301 of these forms are indeed cocrystals. Additionally, 87 salt-cocrystal continuum forms are identified and 16 cocrystals are classified as possible salts. These 16 problematic structures are further investigated and for seven of them, single crystals were grown and their structure determined using single-crystal X-ray diffraction. Among the phases exhibiting salt-like behaviour, five of them are identified as salts. In some cases, rSCAN alone gives unreliable results for strong hydrogen bonds, but these discrepancies are often corrected using better-renormalized or hybrid functionals (i.e. r2SCAN, PBE0 and PBE50). For future calculations, we recommend using the r2SCAN functional for salt-cocrystal differentiation, as it provides reliable results for O-H...N bonds longer than 2.554 (5) Å. The r2SCAN functional offers a good balance between accuracy and computational efficiency for systems with longer O-H...N bonds.</p>","PeriodicalId":7320,"journal":{"name":"Acta crystallographica Section B, Structural science, crystal engineering and materials","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11970119/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143514324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}