Pub Date : 2024-08-06DOI: 10.1107/s2052520624004268
J. M. Perez-Mato, B. J. Campbell, V. O. Garlea, F. Damay, G. Aurelio, M. Avdeev, M. T. Fernández-Díaz, M. S. Henriques, D. Khalyavin, S. Lee, V. Pomjakushin, N. Terada, O. Zaharko, J. Campo, O. Fabelo, D. B. Litvin, V. Petricek, S. Rayaprol, J. Rodriguez-Carvajal, R. Von Dreele
A report from the International Union of Crystallography Commission on Magnetic Structures outlining the recommendations for communicating commensurate magnetic structures.
国际晶体学联合会磁结构委员会的一份报告，概述了有关沟通相称磁结构的建议。
{"title":"Guidelines for communicating commensurate magnetic structures. A report of the International Union of Crystallography Commission on Magnetic Structures","authors":"J. M. Perez-Mato, B. J. Campbell, V. O. Garlea, F. Damay, G. Aurelio, M. Avdeev, M. T. Fernández-Díaz, M. S. Henriques, D. Khalyavin, S. Lee, V. Pomjakushin, N. Terada, O. Zaharko, J. Campo, O. Fabelo, D. B. Litvin, V. Petricek, S. Rayaprol, J. Rodriguez-Carvajal, R. Von Dreele","doi":"10.1107/s2052520624004268","DOIUrl":"https://doi.org/10.1107/s2052520624004268","url":null,"abstract":"A report from the International Union of Crystallography Commission on Magnetic Structures outlining the recommendations for communicating commensurate magnetic structures.","PeriodicalId":501081,"journal":{"name":"Acta Crystallographica Section B","volume":"137 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141969154","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-06DOI: 10.1107/s2052520624005675
Ilia A. Subbotin, E. M. Pashaev, Stanislav S. Dubinin, Vladimir V. Izyurov, Anna O. Belyaeva, Oleg A. Kondratiev, Kristina A. Merencova, Mikhail S. Artemiev, Aleksandr P. Nosov
An algorithm is proposed for determining the orientational relationships and crystal unit-cell parameters of thin films using a laboratory X-ray diffractometer and stereographic projections. It is illustrated by the treatment of experimental data obtained for yttrium orthoferrite YFeO3 films on single crystalline sapphire (Al2O3) substrates for film thicknesses in the range from 100 to 7000 Å. Precise determination of unit-cell constants and angles is possible by combining the results of X-ray measurements made in the in-plane and out-of-plane geometries. The unit-cell unit parameters and orientation relationships for thin films were determined. For the studied films, typical errors in determining unit-cell parameters and angles are better than 0.17 Å and 0.17°, respectively.
提出了一种利用实验室 X 射线衍射仪和立体投影确定薄膜的取向关系和晶体单元参数的算法。该算法通过处理单晶蓝宝石（Al2O3）基底上的正铁钇YFeO3薄膜的实验数据进行说明，薄膜厚度范围为 100 至 7000 Å。通过结合平面内和平面外几何形状的 X 射线测量结果，可以精确测定晶胞常数和角度。薄膜的单胞参数和取向关系已经确定。对于所研究的薄膜，确定单位晶胞参数和角度的典型误差分别优于 0.17 Å 和 0.17°。
{"title":"Orientational and crystallographic relationships in thin films of yttrium orthoferrite on sapphire substrates","authors":"Ilia A. Subbotin, E. M. Pashaev, Stanislav S. Dubinin, Vladimir V. Izyurov, Anna O. Belyaeva, Oleg A. Kondratiev, Kristina A. Merencova, Mikhail S. Artemiev, Aleksandr P. Nosov","doi":"10.1107/s2052520624005675","DOIUrl":"https://doi.org/10.1107/s2052520624005675","url":null,"abstract":"An algorithm is proposed for determining the orientational relationships and crystal unit-cell parameters of thin films using a laboratory X-ray diffractometer and stereographic projections. It is illustrated by the treatment of experimental data obtained for yttrium orthoferrite YFeO<sub>3</sub> films on single crystalline sapphire (Al<sub>2</sub>O<sub>3</sub>) substrates for film thicknesses in the range from 100 to 7000 Å. Precise determination of unit-cell constants and angles is possible by combining the results of X-ray measurements made in the in-plane and out-of-plane geometries. The unit-cell unit parameters and orientation relationships for thin films were determined. For the studied films, typical errors in determining unit-cell parameters and angles are better than 0.17 Å and 0.17°, respectively.","PeriodicalId":501081,"journal":{"name":"Acta Crystallographica Section B","volume":"24 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141969155","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-31DOI: 10.1107/s205252062400492x
{"title":"Synthesis and structural characterization of a new dinuclear platinum(III) complex, [Pt2Cl4(NH3)2{μ-HN=C(O)But}2], and Synthesis and structure of two novel trans-platinum complexes. Addenda and errata","authors":"","doi":"10.1107/s205252062400492x","DOIUrl":"https://doi.org/10.1107/s205252062400492x","url":null,"abstract":"","PeriodicalId":501081,"journal":{"name":"Acta Crystallographica Section B","volume":"51 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141938706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-29DOI: 10.1107/s2052520624002427
Rahul Shukla, Anik Sen
Hydrogen-bonding and halogen-bonding interactions are important noncovalent interactions that play a significant role in the crystal structure of organic molecules. An in-depth analysis is given of the crystal packing of two previously reported crystal structures of dihalogenated 1,2,4-triazole derivatives, namely 3,5-dichloro-1H-1,2,4-triazole and 3,5-dibromo-1H-1,2,4-triazole. This work provides insights into the complex interplay of hydrogen-bonding and halogen-bonding interactions resulting in the formation of multiple trimeric motifs in the crystal structure of 1,2,4-triazole derivatives. Analysis of the crystal packing of these isostructural crystal structures revealed that the molecular arrangement in these molecules is primarily stabilized by the formation of different trimeric motifs stabilized by N—H…N hydrogen bonds, N—H…X (X = Cl/Br) halogen bonds and C—X…X halogen-bonding interactions. Computational studies further revealed that all these trimers are energetically stable. A crystallographic database search further reveals that while the cyclic trimers reported in this study are present in other molecules, structures analyzed in this study are the sole instances where all are present simultaneously.
{"title":"Hydrogen- and halogen-bonding-directed trimeric supramolecular motifs in dihalogenated 1,2,4-triazoles","authors":"Rahul Shukla, Anik Sen","doi":"10.1107/s2052520624002427","DOIUrl":"https://doi.org/10.1107/s2052520624002427","url":null,"abstract":"Hydrogen-bonding and halogen-bonding interactions are important noncovalent interactions that play a significant role in the crystal structure of organic molecules. An in-depth analysis is given of the crystal packing of two previously reported crystal structures of dihalogenated 1,2,4-triazole derivatives, namely 3,5-dichloro-1<i>H</i>-1,2,4-triazole and 3,5-dibromo-1<i>H</i>-1,2,4-triazole. This work provides insights into the complex interplay of hydrogen-bonding and halogen-bonding interactions resulting in the formation of multiple trimeric motifs in the crystal structure of 1,2,4-triazole derivatives. Analysis of the crystal packing of these isostructural crystal structures revealed that the molecular arrangement in these molecules is primarily stabilized by the formation of different trimeric motifs stabilized by N—H…N hydrogen bonds, N—H…<i>X</i> (<i>X</i> = Cl/Br) halogen bonds and C—<i>X</i>…<i>X</i> halogen-bonding interactions. Computational studies further revealed that all these trimers are energetically stable. A crystallographic database search further reveals that while the cyclic trimers reported in this study are present in other molecules, structures analyzed in this study are the sole instances where all are present simultaneously.","PeriodicalId":501081,"journal":{"name":"Acta Crystallographica Section B","volume":"35 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140808832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-27DOI: 10.1107/s2052520623009393
Alexander Talis, Yaroslav Kucherinenko
Non-crystallographic fractional screw axes are inherent to the constructions of n-dimensional crystallography, where 3 < n ≤ 8. This fact allows one to consider experimentally obtained helices as periodic approximants of helices from the four-dimensional {3,3,5} polytope and its derivative constructions. For the tetrahedral Coxeter–Boerdijk helix (tetrahelix) with a 30/11 axis from the {3,3,5} polytope, approximants with 11/4 and 8/3 axes in three-dimensional Euclidean space are considered. These determine the structure of rods composed of deformed tetrahedra in close-packed crystals of α-Mn and β-Mn. In the {3,3,5} polytope, highlighted here for the first time, is a 40-vertex helix with a 20/9 axis composed of seven-vertex quadruples of tetrahedra (tetrablocks), whose 7/3 approximants determine in a crystal of an α-Mn rod of deformed tetrablocks with the same period as the 11/4 approximant of the tetrahelix. In the spaces of the three-dimensional sphere and , the parameters of 20/9, 40/9 and 40/11 helices, as well as of their 20- and 40-vertex approximants, are calculated. The parameters of the approximant of the 40/11 helix in correspond to experimentally determined parameters of the α-helix, which allows us to explain the versatility of the α-helix in proteins by the symmetry of the polytope. The set of fractional axes of all periodic approximants of helices with 30/11, 20/9, 40/9, 40/11 axes, as well as the powers of these axes, are combined into a tetrahedral-polytope class of 50 basic axes. The basic axes as well as composite (defined as a combination of basic ones) fractional axes of this class cover all fractional axes known to us according to literature data for polymers, biopolymers and close-packed metals.
{"title":"Non-crystallographic helices in polymers and close-packed metallic crystals determined by the four-dimensional counterpart of the icosahedron","authors":"Alexander Talis, Yaroslav Kucherinenko","doi":"10.1107/s2052520623009393","DOIUrl":"https://doi.org/10.1107/s2052520623009393","url":null,"abstract":"Non-crystallographic fractional screw axes are inherent to the constructions of <i>n</i>-dimensional crystallography, where 3 < <i>n</i> ≤ 8. This fact allows one to consider experimentally obtained helices as periodic approximants of helices from the four-dimensional {3,3,5} polytope and its derivative constructions. For the tetrahedral Coxeter–Boerdijk helix (tetrahelix) with a 30/11 axis from the {3,3,5} polytope, approximants with 11/4 and 8/3 axes in three-dimensional Euclidean space <img alt=\"{bb E}^{3}\" loading=\"lazy\" src=\"/cms/asset/56d0b94f-3725-4a26-b725-dee021acf6a4/ayb2yh5028-gra-0001.png\"/> are considered. These determine the structure of rods composed of deformed tetrahedra in close-packed crystals of α-Mn and β-Mn. In the {3,3,5} polytope, highlighted here for the first time, is a 40-vertex helix with a 20/9 axis composed of seven-vertex quadruples of tetrahedra (tetrablocks), whose 7/3 approximants determine in a crystal of an α-Mn rod of deformed tetrablocks with the same period as the 11/4 approximant of the tetrahelix. In the spaces of the three-dimensional sphere and <img alt=\"{bb E}^{3}\" loading=\"lazy\" src=\"/cms/asset/56d0b94f-3725-4a26-b725-dee021acf6a4/ayb2yh5028-gra-0001.png\"/>, the parameters of 20/9, 40/9 and 40/11 helices, as well as of their 20- and 40-vertex approximants, are calculated. The parameters of the approximant of the 40/11 helix in <img alt=\"{bb E}^{3}\" loading=\"lazy\" src=\"/cms/asset/56d0b94f-3725-4a26-b725-dee021acf6a4/ayb2yh5028-gra-0001.png\"/> correspond to experimentally determined parameters of the α-helix, which allows us to explain the versatility of the α-helix in proteins by the symmetry of the polytope. The set of fractional axes of all periodic approximants of helices with 30/11, 20/9, 40/9, 40/11 axes, as well as the powers of these axes, are combined into a tetrahedral-polytope class of 50 basic axes. The basic axes as well as composite (defined as a combination of basic ones) fractional axes of this class cover all fractional axes known to us according to literature data for polymers, biopolymers and close-packed metals.","PeriodicalId":501081,"journal":{"name":"Acta Crystallographica Section B","volume":" 122","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138494506","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
are considered. These determine the structure of rods composed of deformed tetrahedra in close-packed crystals of α-Mn and β-Mn. In the {3,3,5} polytope, highlighted here for the first time, is a 40-vertex helix with a 20/9 axis composed of seven-vertex quadruples of tetrahedra (tetrablocks), whose 7/3 approximants determine in a crystal of an α-Mn rod of deformed tetrablocks with the same period as the 11/4 approximant of the tetrahelix. In the spaces of the three-dimensional sphere and 
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