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

{"title":"Novel dense crystal structure of high-pressure synthetic K₈Ca₃(CO₃)₇ as described through cation-carbon nets.","authors":"Anna Yu Likhacheva, Sergey V Rashchenko, Mark A Ignatov, Alexandr V Romanenko, Anton F Shatsky","doi":"10.1107/S2052520625007929","DOIUrl":"https://doi.org/10.1107/S2052520625007929","url":null,"abstract":"<p><p>K₈Ca₃(CO₃)₇ was synthesized at 1200°C and 6 GPa. Its layered triclinic crystal structure presents a new type characteristic of high-pressure K-Ca carbonates. It is also the second example of K/Ca disorder coupled with orientational disorder of carbonate anions. Descriptions based on the most symmetric (tri/hexagonal) and the densest (krd-type) cation-carbon nets reveal its peculiarities and common features with the crystal structures of chemically related carbonates. The four-layered ABA'B packing in K₈Ca₃(CO₃)₇ is based on hexagonal cation nets, wherein carbon atoms occupy two types of positions. Most of the carbon atoms are localized close to net B, within the centers of triangular loops. This forms a bütschliite layer, which is found in other alkali-bearing carbonates and is composed of alkali cations. Its presence in the K₈Ca₃(CO₃)₇ crystal structure implies that the K/Ca disorder is incomplete. In nets A and A', carbon atoms replace the cations at some nodes, resulting in the aggregation and increased concentration of carbon atoms and their stronger mixing with cations in the densest (krd-type) nets. Thus, a new type of densest mixed net is formed in the K₈Ca₃(CO₃)₇ crystal structure. A quantitative measure of the packing density of high-pressure K-Ca carbonates is the reticular density of the symmetric atomic nets, as well as the distance between the densest nets.</p>","PeriodicalId":7320,"journal":{"name":"Acta crystallographica Section B, Structural science, crystal engineering and materials","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145184464","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":"Investigation of thermal behavior of monoclinic ludwigite-type oxoborate Cu₂FeO₂(BO₃) in the range 300-1273 K.","authors":"Yaroslav P Biryukov, Rimma S Bubnova, Andrey P Shablinskii, Yulia S Gokhfeld, Natalya V Kazak, Margarita S Avdontceva, Maria G Krzhizhanovskaya, Sergey N Vereshchagin","doi":"10.1107/S2052520625007413","DOIUrl":"https://doi.org/10.1107/S2052520625007413","url":null,"abstract":"<p><p>The crystal structure of synthetic ludwigite-type oxoborate Cu₂FeO₂(BO₃) was first determined using in situ high-temperature single-crystal X-ray diffraction data collected at 300, 800 and 950 K. The structure is described as a heteropolyhedral framework composed of edge- and vertex-sharing [MO₆]^n- (M = Cu²⁺, Fe³⁺) octahedra that form extended zigzag chains in the bc plane with isolated trigonal planar [BO₃]^3- located in triangular cavities of the cationic framework. Oxo-centered [OM₄]ⁿ⁺ tetrahedra and [OM₅]ⁿ⁺ tetragonal pyramids are observed and described for the first time. The structure is disordered: the Cu1 and Cu3 sites are fully occupied by the Cu²⁺ ions, while the M2 and M4 sites are occupied by the Cu²⁺ and Fe³⁺ ions in ratios of 0.59:0.41 and 0.20:0.80, respectively. The O4 site is split into two sites, O4A and O4B, which leads to the formation of distorted [M2O₆]^n-, Cu3O₆]^n- and [M4O₆]^n- polyhedra. Thermal behavior of Cu₂FeO₂(BO₃) was investigated using in situ high-temperature single-crystal and powder X-ray diffraction, simultaneous thermal analysis and high-temperature heat capacity measurements. Unusual behavior of the unit-cell parameters and specific heat is observed at ∼690 K. The borate is stable up to ∼1040 K, when an incomplete solid-phase decomposition begins with the formation of CuO and (Cu,Fe)₃O₄ phases. The anisotropy of thermal expansion is weak and it is explained by (i) the preferable orientation of the most chemically rigid [BO₃]^3- units, (ii) the theory of shear deformations of the monoclinic ac plane and (iii) an arrangement of the oxo-centered [O₂M₇]ⁿ⁺ and [O₂M₈]ⁿ⁺ double chains. Volume expansion increases with an increase in temperature from 24.6 × 10^-6 K^-1 (at 300 K) to 35.4 × 10^-6 K^-1 (at 1000 K). The degree of anisotropy of the expansion of Cu₂FeO₂(BO₃) is similar to that of orthorhombic ludwigite-type oxoborates.</p>","PeriodicalId":7320,"journal":{"name":"Acta crystallographica Section B, Structural science, crystal engineering and materials","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145184488","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":"Solvated forms of carbenoxolone - different degrees of structural similarities.","authors":"Bartłomiej Kobus, Zuzanna Spychała, Oliwia Kleybor, Agata Ostrowska, Barbara Wicher, Ewa Tykarska","doi":"10.1107/S205252062500798X","DOIUrl":"https://doi.org/10.1107/S205252062500798X","url":null,"abstract":"<p><p>Carbenoxolone (CBXH₂) is a biologically active compound first synthesized in the late 1950s. Four new solvates of CBXH₂ with propan-1-ol, tert-butanol, dimethylformamide and dimethyl sulfoxide were obtained and characterized using single-crystal and powder X-ray diffraction along with thermal analyses. Ribbons and layers, recurring building motifs in these structures, are primarily based on dispersion interactions. The degree of similarity (1D, 2D or 3D) between these new structures and four CBXH₂ structures from the Cambridge Structural Database was evaluated using geometrical parameters and XPac calculations.</p>","PeriodicalId":7320,"journal":{"name":"Acta crystallographica Section B, Structural science, crystal engineering and materials","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145197770","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":"Role of restraints on hydrogen atoms in Hirshfeld atom refinement: the case of tri-aspartic acid trihydrate.","authors":"Ravish Sankolli, Lorraine A Malaspina, Oleg V Dolomanov, Peter Luger, Julian J Holstein, Carsten Paulmann, Wolfgang Morgenroth, Florian Kleemiss, Birger Dittrich, Simon Grabowsky","doi":"10.1107/S2052520625006110","DOIUrl":"https://doi.org/10.1107/S2052520625006110","url":null,"abstract":"<p><p>Two polymorphs of L-Asp-L-Asp-L-Asp (DDD) trihydrate as model compounds for biologically important proton-shuttle reactions were investigated with the quantum-crystallographic refinement technique Hirshfeld atom refinement (HAR). With HAR, hydrogen-atom positions are refined freely against the X-ray diffraction data and yield X-H bond distances close to those from neutron diffraction. However, the X-ray data of DDD trihydrate do not contain sufficient information to refine anisotropic displacement parameters (ADPs) for the hydrogen atoms, although the data quality is comparable to that of typical oligopeptide or protein datasets, including those with disordered fragments. Therefore, the following restraints were tested for the hydrogen-atom ADPs using NoSpherA2/olex2.refine: a restraint that approximates isotropic behaviour (ISOR), a restraint that enforces similar movement in any direction (SIMU), a rigid-bond restraint (DELU) and an advanced rigid-bond restraint (RIGU). Although it was found that there is no significant influence of the restraint weights and corresponding ADP values on the X-H distances, some recommendations on hydrogen-atom ADP restraint weights to be used in HAR are given. For ISOR, the suggested values are 10 times smaller (stricter) than the default values for non-hydrogen atoms in independent atom model (IAM) refinements, whereas those for RIGU are suggested to be less strict.</p>","PeriodicalId":7320,"journal":{"name":"Acta crystallographica Section B, Structural science, crystal engineering and materials","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145249247","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":"Structural phase transitions, dehydration and decomposition of ammonium hypodiphosphates.","authors":"Katarzyna A Ślepokura, Paulina Kurowska, Daria Budzikur-Maciąg, Vasyl Kinzhybalo","doi":"10.1107/S2052520625004408","DOIUrl":"10.1107/S2052520625004408","url":null,"abstract":"<p><p>The ferroelectric diammonium hypodiphosphate, (NH₄)₂(H₂P₂O₆) (3), is the only known so far ammonium salt of hypodiphosphoric acid, H₄P₂O₆. A series of seven new ammonium salts is reported: triclinic (P1) (1) and monoclinic (C2/c) (2) polymorphs of monoammonium (NH₄)(H₃P₂O₆), isostructural (NH₄)₅(H₂P₂O₆)(HP₂O₆)·H₂O (4) and (NH₄)₃(HP₂O₆) (5), and tetraammonium (NH₄)₄(P₂O₆) (6), (NH₄)₄(P₂O₆)·H₂O (7) and (NH₄)₄(P₂O₆)·2H₂O (8). Monoammonium hypodiphosphates 1 and 2 crystallize in perovskite-type structures. Form 1 undergoes an order-disorder phase transition related to the dynamics of ammonium cations, the unit-cell doubling and no change in space group type. Dehydration-decomposition of 4 leads to the equimolar mixture of 3 and 5, whereas dehydration of dihydrate 8 proceeds in two steps, resulting in the formation of monohydrate 7 and then anhydrate 6. Compound 7 undergoes a reversible phase transition (P2₁/c ↔ C2/c) concerned with the reorganization of the hydrogen-bond network. Thermal analysis (DSC and TG-DTA) and variable-temperature microsample powder X-ray diffraction were used to analyse the phase transitions, dehydration and decomposition processes.</p>","PeriodicalId":7320,"journal":{"name":"Acta crystallographica Section B, Structural science, crystal engineering and materials","volume":" ","pages":"407-417"},"PeriodicalIF":1.3,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144582803","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":"Structures of phosphonitrides in light of the extended Zintl-Klemm concept.","authors":"Angel Vegas, Hussien H Osman, Alfonso Muñoz, Vladislav A Blatov, Francisco Javier Manjón","doi":"10.1107/S2052520625004263","DOIUrl":"10.1107/S2052520625004263","url":null,"abstract":"<p><p>The extended Zintl-Klemm concept (EZKC) is applied to explain the crystalline structures of phosphonitrides (also known as nitridophosphates in the chemical literature). The examples of (AE)₂AlP₈N₁₅(NH) (AE = Ca, Sr, Ba), Ge^IVPN₃ and MP₂N₄ (M = Be, Ca, Sr, Ba, Ge^II) are mainly discussed, although the examples of LiGaGe and LiGaGeO₄ have been also commented on due to their relation with BeP₂N₄. It is shown that the EZKC provides a better understanding of the structures of these compounds than in previous descriptions. In most of these nitrides, P atoms behave as pseudo-Si atoms and N atoms behave as pseudo-O atoms, so providing a good explanation for the four-connectivity of P atoms forming PN₄ units, which behave as pseudo-SiO₄ units like the SiO₄ units in many polymorphs of SiO₂. In addition, the EZKC shows that the notation of these compounds as phosphonitrides is more appropriate than as nitridophosphates because N atoms act as the anions in these compounds.</p>","PeriodicalId":7320,"journal":{"name":"Acta crystallographica Section B, Structural science, crystal engineering and materials","volume":" ","pages":"378-394"},"PeriodicalIF":1.3,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12322934/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144582804","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":"A linear/quadratic order parameter coupling description of the Verwey transition in magnetite, Fe₃O₄.","authors":"Michael A Carpenter, Richard J Harrison, James Shaw-Stewart, Kanta Adachi, Mark S Senn, Christopher J Howard","doi":"10.1107/S2052520625004779","DOIUrl":"10.1107/S2052520625004779","url":null,"abstract":"<p><p>The change in symmetry Fd3m → Cc at the Verwey transition in magnetite puts it in a class of phase transitions with linear/quadratic coupling between two separate order parameters. Direct coupling between an order parameter Q_e, to represent an electronic instability, and an order parameter Q_co, to represent cation charge ordering, has the form λQ_eQ_co², with T_c(Q_e) < T_c(Q_co), but there must also be indirect coupling through the common strain, e₆, due to strain coupling terms λe₆Q_e and λe₆Q_co². Q_e has the symmetry of irrep Γ₅⁺ while the pattern of cation charge ordering of Fe²⁺ and Fe³⁺ on octahedral sites depends on some combination of irreps Δ₅, X₁, X₃, W₁ and W₂. The software package ISOVIZ has been used to show how reported patterns of order for the simplified structure in space group P2/c can be understood in terms of a linearly dependent mix of patterns with symmetry Δ₅ and X₁, so that Q_co can be treated in the first instance as though it has the symmetry of Δ₅. Spontaneous strains calculated from published lattice parameters and symmetry-adapted atomic displacements from previous structural refinements in space group Cc have been used to confirm that the two order parameters have different temperature dependences, consistent with this phenomenological treatment. The effect of chemical doping can be understood in terms of the development of local strain heterogeneity which acts to suppress the macroscopic strains and which appears to have a greater influence on charge ordering than on the electronic structure.</p>","PeriodicalId":7320,"journal":{"name":"Acta crystallographica Section B, Structural science, crystal engineering and materials","volume":" ","pages":"427-436"},"PeriodicalIF":1.3,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12322932/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144590230","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":"New insights into structural diversity of open-framework silicates inspired by the exploration of the Cs₂O-CaO-SiO₂ system.","authors":"Sergey M Aksenov","doi":"10.1107/S2052520625005189","DOIUrl":"10.1107/S2052520625005189","url":null,"abstract":"<p><p>The structure of unique compound Cs₄Ca[Si₈O₁₉] reported recently by Kahlenberg [(2025), Acta Cryst. B81, 325-336] contributes to the broader understanding of structure-property relationships in open-framework silicates (as well as silicates with mixed octahedral-tetrahedral frameworks), with potential implications for ion-exchange, catalysis, and materials with tailored thermal expansion.</p>","PeriodicalId":7320,"journal":{"name":"Acta crystallographica Section B, Structural science, crystal engineering and materials","volume":" ","pages":"376-377"},"PeriodicalIF":1.3,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144582802","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 role of the solvent molecule in the crystal packing arrangements of hydrated salts formed by ethacridine and fluorobenzoic acids.","authors":"Artur Mirocki, Mattia Lopresti","doi":"10.1107/S2052520625004433","DOIUrl":"10.1107/S2052520625004433","url":null,"abstract":"<p><p>Three novel hydrated salts of ethacridine: 2-fluorobenzoate dihydrate, 3-fluorobenzoate monohydrate and 4-fluorobenzoate monohydrate were synthesized and structurally characterized using single-crystal X-ray diffraction. Analysis of intermolecular interactions in the crystal packing revealed that the number of water molecules in the asymmetric unit determines the formation of distinct centrosymmetric supramolecular synthons: [...water...acid...]₂ and [...water...water...acid...]₂. Hirshfeld surface analysis and lattice energy calculations were exploited to characterize intermolecular interactions and to elucidate the influence of small stereochemical differences among the three fluorobenzoate isomers on the crystal packing of the obtained molecular complexes.</p>","PeriodicalId":7320,"journal":{"name":"Acta crystallographica Section B, Structural science, crystal engineering and materials","volume":" ","pages":"395-406"},"PeriodicalIF":1.3,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144582805","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":"Multidisciplinary study of thorium mobility: formation of turkestanite and steacyite analogues, and structural insights using an XRD-directed microcrystal preparation technique.","authors":"M Stachowicz, B Bagiński, D E Harlov, P Jokubauskas, J Kotowski, W Matyszczak, A Dąbrowska, R Macdonald","doi":"10.1107/S2052520625004822","DOIUrl":"10.1107/S2052520625004822","url":null,"abstract":"<p><p>Minerals of the ekanite group typically contain Th, U or REE (rare earth elements) as primary structural constituents. The ^CNa analogues of turkestanite, ^ATh^B(Ca,Na)^C(K_1-x□_x)^T(Si₈O₂₀) (□ is vacancy), and steacyite, ^ATh^B(Ca,Na)^C(K_1-x□_x)^T(Si₈O₂₀), isostructural minerals of the ekanite group, were experimentally synthesized during hydrothermal alteration of chevkinite-(Ce). The experiment was conducted at 550°C, 200 MPa, at an oxygen fugacity approximately equivalent to the Ni-NiO (NNO) buffer with NaF and Ca(PO₄)₂ added to the hydrous fluid. Both phases formed as a replacement of chevkinite-(Ce) and earlier alteration products. Their identity was confirmed by electron probe microanalysis and electron backscatter diffraction as ^CNa analogues of turkestanite and steacyite. Further SCXRD, and Raman spectroscopy analyses confirmed that it is a new ^CNa analogue with respect to the ekanite mineral group. Raman spectroscopy revealed the presence of H₂O within the crystal structure. A dedicated FIB workflow was designed to extract single crystals ready for SCXRD analysis. Compositionally, the phase is Na rich and depleted in K, REE and Fe. The mean formula based on 20 O atoms can be written as ^A(Th_0.94U_0.03)_0.97^B(Na_0.96Ca_0.90Mn_0.11Ce_0.02Nd_0.01Fe_0.01)_2.0^C(Na_0.83K_0.07)_0.9^TSi_8.05O₂₀·0.1^C(H₂O). It crystallizes in space group P4/mcc with a = 7.4757 (2) Å, c = 14.9658 (7) Å, V = 836.38 (6) ų, and Z = 2. Compositional variation is represented mainly by the relationship Ca²⁺ + □ → 2Na⁺, where □ is a vacancy which can also be filled by H₂O during crystallization. The synthesis from this study represents the first record of ^CNa analogues of turkestanite and steacyite. A dedicated microcrystal selection technique is presented allowing for easy single-crystal X-ray diffraction.</p>","PeriodicalId":7320,"journal":{"name":"Acta crystallographica Section B, Structural science, crystal engineering and materials","volume":"81 Pt 4","pages":"418-426"},"PeriodicalIF":1.3,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12322933/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144793242","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}