Pub Date : 2022-03-30DOI: 10.1107/s2052520622003067
M. Bujak, M. Podsiadło, A. Katrusiak
{"title":"Response to comment on Properties and interactions - melting point of tribromobenzene isomers.","authors":"M. Bujak, M. Podsiadło, A. Katrusiak","doi":"10.1107/s2052520622003067","DOIUrl":"https://doi.org/10.1107/s2052520622003067","url":null,"abstract":"","PeriodicalId":7080,"journal":{"name":"Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials","volume":"62 1","pages":"276-278"},"PeriodicalIF":0.0,"publicationDate":"2022-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76210057","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 : 2022-03-30DOI: 10.1107/s2052520621010374
J. van de Streek
{"title":"Comment on the article Properties and interactions - melting point of tribromobenzene isomers.","authors":"J. van de Streek","doi":"10.1107/s2052520621010374","DOIUrl":"https://doi.org/10.1107/s2052520621010374","url":null,"abstract":"","PeriodicalId":7080,"journal":{"name":"Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials","volume":"1 1","pages":"274-275"},"PeriodicalIF":0.0,"publicationDate":"2022-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74308658","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 : 2022-03-24DOI: 10.1107/S205252062200227X
Tsunetomo Yamada
A four-dimensional structure model for the Ba–Ti–O dodecagonal quasicrystal is described.
描述了Ba-Ti-O十二角准晶体的四维结构模型。
{"title":"A four-dimensional model for the Ba–Ti–O dodecagonal quasicrystal","authors":"Tsunetomo Yamada","doi":"10.1107/S205252062200227X","DOIUrl":"https://doi.org/10.1107/S205252062200227X","url":null,"abstract":"A four-dimensional structure model for the Ba–Ti–O dodecagonal quasicrystal is described.","PeriodicalId":7080,"journal":{"name":"Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials","volume":"4 1","pages":"247 - 252"},"PeriodicalIF":0.0,"publicationDate":"2022-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76736939","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 : 2022-03-22DOI: 10.1107/s2052520622001366
H. Bürgi
Attempting to appreciate Jack’s merits in science runs the risk of bias. This danger can be minimized, however, by listening to Jack’s own words. In an essay entitled ‘La Primavera’ (Dunitz, 2013), Jack reflects on his formative years, the time before he took his position at ETHZ in 1957; in 2021 Jack looked back on his long life in science in two interviews conducted by E. Carreira, his colleague at ETHZ and editor-in-chief of the Journal of the American Chemical Society; Jack’s relationship vis-à-vis molecular biology is the theme of a conversation with E. Carafoli conducted in 2017 (Carafoli, 2017); in the journal Chimia Jack chats about exploring the world of science, his wanderings and his life in Zürich, inside and outside of ETHZ (Weber, 2011). This account attempts to portray Jack’s most important achievements against the background of concepts and activities prevailing during the time of his involvement in science. Hargittai (2021) writes in a similar vein. Jack was born on 29 March 1923 in Glasgow (Scotland) where he grew up into the golden age of X-ray and chemical crystallography. During his education his high school teacher got him interested in the sciences and World War II brought him to the group of the renowned crystallographer J. Monteath Robertson to do PhD research. He learned the art and science of structure determination: art because structures like the ones Jack worked on, with H, C and O atoms only, had first to be guessed at; direct methods had not yet been invented; science to the extent there were systematic heavy atom methods such as the Patterson method and the isomorphous replacement method, the latter invented by his supervisor. After gaining his PhD in 1944, his journeyman’s years had him work with actual and future Nobel laureates, Dorothy Hodgkin in Oxford, Linus Pauling at ISSN 2052-5206
试图欣赏杰克在科学方面的优点有偏见的风险。然而，通过听杰克自己的话，这种危险可以降到最低。在一篇题为“La Primavera”(Dunitz, 2013)的文章中，Jack回顾了他的成长岁月，1957年他在ETHZ任职之前;2021年，杰克接受了他在ETHZ的同事、《美国化学会杂志》(Journal of American Chemical Society)主编E. Carreira的两次采访，回顾了他漫长的科学生涯;杰克与-à-vis分子生物学的关系是2017年与E. Carafoli进行的对话的主题(Carafoli, 2017);在《Chimia》杂志上，杰克谈到了探索科学的世界，他的漫游和他在 rich的生活，在ETHZ内外(Weber, 2011)。这本书试图在杰克从事科学研究期间流行的概念和活动的背景下描绘他最重要的成就。哈吉泰(Hargittai, 2021)的写作风格与此类似。杰克于1923年3月29日出生在苏格兰的格拉斯哥，在那里他成长在x射线和化学晶体学的黄金时代。在他接受教育期间，他的高中老师使他对科学产生了兴趣，第二次世界大战使他加入了著名的晶体学家J.蒙特思罗伯逊的小组，进行博士研究。他学会了结构确定的艺术和科学:艺术是因为像杰克研究的结构，只有氢、碳和氧原子，首先要猜出来;直接的方法还没有发明;有系统的重原子方法，如帕特森方法和同构置换法，后者是由他的导师发明的。1944年获得博士学位后，他与牛津大学的多萝西·霍奇金(Dorothy Hodgkin)和ISSN 2052-5206的莱纳斯·鲍林(Linus Pauling)等实际和未来的诺贝尔奖得主一起工作
{"title":"Jack David Dunitz (1923-2021) and chemical crystallography.","authors":"H. Bürgi","doi":"10.1107/s2052520622001366","DOIUrl":"https://doi.org/10.1107/s2052520622001366","url":null,"abstract":"Attempting to appreciate Jack’s merits in science runs the risk of bias. This danger can be minimized, however, by listening to Jack’s own words. In an essay entitled ‘La Primavera’ (Dunitz, 2013), Jack reflects on his formative years, the time before he took his position at ETHZ in 1957; in 2021 Jack looked back on his long life in science in two interviews conducted by E. Carreira, his colleague at ETHZ and editor-in-chief of the Journal of the American Chemical Society; Jack’s relationship vis-à-vis molecular biology is the theme of a conversation with E. Carafoli conducted in 2017 (Carafoli, 2017); in the journal Chimia Jack chats about exploring the world of science, his wanderings and his life in Zürich, inside and outside of ETHZ (Weber, 2011). This account attempts to portray Jack’s most important achievements against the background of concepts and activities prevailing during the time of his involvement in science. Hargittai (2021) writes in a similar vein. Jack was born on 29 March 1923 in Glasgow (Scotland) where he grew up into the golden age of X-ray and chemical crystallography. During his education his high school teacher got him interested in the sciences and World War II brought him to the group of the renowned crystallographer J. Monteath Robertson to do PhD research. He learned the art and science of structure determination: art because structures like the ones Jack worked on, with H, C and O atoms only, had first to be guessed at; direct methods had not yet been invented; science to the extent there were systematic heavy atom methods such as the Patterson method and the isomorphous replacement method, the latter invented by his supervisor. After gaining his PhD in 1944, his journeyman’s years had him work with actual and future Nobel laureates, Dorothy Hodgkin in Oxford, Linus Pauling at ISSN 2052-5206","PeriodicalId":7080,"journal":{"name":"Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials","volume":"74 1","pages":"270-273"},"PeriodicalIF":0.0,"publicationDate":"2022-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89433663","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 : 2022-03-17DOI: 10.1107/s2052520622001469
C. Lecomte
crystallographic crystal band transport metal-insulators magnetic and dielectric properties, optical mechanical phase diagrams, synthetic strategies,
晶体学晶体带输运金属绝缘体的磁性和介电性能，光学力学相图，合成策略，
{"title":"Principles of Inorganic Materials Design, third edition. By John N. Lalena, David A. Cleary, Olivier B. M. Hardouin Duparc. Wiley, 2020. Hardcover, pp. 720. Price EUR 166.70. ISBN 978-1-119-48683-1.","authors":"C. Lecomte","doi":"10.1107/s2052520622001469","DOIUrl":"https://doi.org/10.1107/s2052520622001469","url":null,"abstract":"crystallographic crystal band transport metal-insulators magnetic and dielectric properties, optical mechanical phase diagrams, synthetic strategies,","PeriodicalId":7080,"journal":{"name":"Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials","volume":"24 1","pages":"279-280"},"PeriodicalIF":0.0,"publicationDate":"2022-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81465870","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 : 2022-03-17DOI: 10.1107/s2052520622001810
Julia Bąkowicz, I. Turowska-Tyrk
The influence of pressure on the course of [4+4] photodimerization in crystals of 9-methylanthracene is presented. The studies were performed at 0.1 and 0.4 GPa. As a result of the reaction at high pressure, crystals of the pure product were obtained, which allowed for monitoring of the reaction until its completion. The initial increase in the unit-cell volume caused by the reaction under ambient conditions was reduced at high pressure due to the decrease in the void volume. Despite the smaller size of the void volume at high pressure, dimer molecules formed during the reaction changed the orientation of the monomer molecules in the crystal structure. The size of the voids above the terminal rings of the monomers correlates with the position of the terminal rings in the dimer. The reaction rate increased at high pressure, indicating that the decrease in the distance between adjacent monomers caused by pressure dominates over the decrease in the void volume. This distance is statistically constant as the reaction progresses, contrary to the reaction at ambient pressure.
{"title":"The role of free space in photochemical reactions in crystals at high pressure - the case of 9-methylanthracene.","authors":"Julia Bąkowicz, I. Turowska-Tyrk","doi":"10.1107/s2052520622001810","DOIUrl":"https://doi.org/10.1107/s2052520622001810","url":null,"abstract":"The influence of pressure on the course of [4+4] photodimerization in crystals of 9-methylanthracene is presented. The studies were performed at 0.1 and 0.4 GPa. As a result of the reaction at high pressure, crystals of the pure product were obtained, which allowed for monitoring of the reaction until its completion. The initial increase in the unit-cell volume caused by the reaction under ambient conditions was reduced at high pressure due to the decrease in the void volume. Despite the smaller size of the void volume at high pressure, dimer molecules formed during the reaction changed the orientation of the monomer molecules in the crystal structure. The size of the voids above the terminal rings of the monomers correlates with the position of the terminal rings in the dimer. The reaction rate increased at high pressure, indicating that the decrease in the distance between adjacent monomers caused by pressure dominates over the decrease in the void volume. This distance is statistically constant as the reaction progresses, contrary to the reaction at ambient pressure.","PeriodicalId":7080,"journal":{"name":"Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials","volume":"168 1","pages":"223-230"},"PeriodicalIF":0.0,"publicationDate":"2022-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90220458","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 : 2022-03-16DOI: 10.1107/s2052520622001731
A. Kremenović, M. Grujić-Brojčin, N. Tomić, V. Lazović, D. Bajuk-Bogdanović, J. Krstić, M. Šćepanović
A size-strain line-broadening analysis of the XRPD patterns and Raman spectra for two anatase/brookite (TiO2)-based nanocomposites with carbon (C) was carried out and the results compared with those of a similar sample free of carbon. The crystal structures and microstructures of anatase and brookite, as well as their relative abundance ratio, have been refined from XRPD data by the Rietveld method (the low amount of carbon is neglected). The XRPD size-strain analysis resulted in reliable structure and microstructure results for both anatase and brookite. The experimental Raman spectra of all the samples in the region 100-200 cm-1 are dominated by a strong feature primarily composed of the most intense modes of anatase (Eg) and brookite (A1g). The anatase crystallite sizes of 14-17 nm, estimated by XRPD, suggest the application of the phonon confinement model (PCM) for the analysis of the anatase Eg mode, whereas the relatively large brookite crystallite size (27-29 nm) does not imply the use of the PCM for the brookite A1g mode. Superposition of the anatase Eg mode profile, calculated by the PCM, and the Lorentzian shape of the brookite A1g mode provide an appropriate simulation of the change in the dominant Raman feature in the spectra of TiO2-based nanocomposites with carbon. Raman spectra measured in the high-frequency range (1000-2000 cm-1) provide information on carbon in the investigated nanocomposite materials. The results from field-emission scanning electron microscope (SEM), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy and nitrogen physisorption measurements support the XRPD and Raman results.
{"title":"Size-strain line-broadening analysis of anatase/brookite (TiO2)-based nanocomposites with carbon (C): XRPD and Raman spectroscopic analysis.","authors":"A. Kremenović, M. Grujić-Brojčin, N. Tomić, V. Lazović, D. Bajuk-Bogdanović, J. Krstić, M. Šćepanović","doi":"10.1107/s2052520622001731","DOIUrl":"https://doi.org/10.1107/s2052520622001731","url":null,"abstract":"A size-strain line-broadening analysis of the XRPD patterns and Raman spectra for two anatase/brookite (TiO2)-based nanocomposites with carbon (C) was carried out and the results compared with those of a similar sample free of carbon. The crystal structures and microstructures of anatase and brookite, as well as their relative abundance ratio, have been refined from XRPD data by the Rietveld method (the low amount of carbon is neglected). The XRPD size-strain analysis resulted in reliable structure and microstructure results for both anatase and brookite. The experimental Raman spectra of all the samples in the region 100-200 cm-1 are dominated by a strong feature primarily composed of the most intense modes of anatase (Eg) and brookite (A1g). The anatase crystallite sizes of 14-17 nm, estimated by XRPD, suggest the application of the phonon confinement model (PCM) for the analysis of the anatase Eg mode, whereas the relatively large brookite crystallite size (27-29 nm) does not imply the use of the PCM for the brookite A1g mode. Superposition of the anatase Eg mode profile, calculated by the PCM, and the Lorentzian shape of the brookite A1g mode provide an appropriate simulation of the change in the dominant Raman feature in the spectra of TiO2-based nanocomposites with carbon. Raman spectra measured in the high-frequency range (1000-2000 cm-1) provide information on carbon in the investigated nanocomposite materials. The results from field-emission scanning electron microscope (SEM), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy and nitrogen physisorption measurements support the XRPD and Raman results.","PeriodicalId":7080,"journal":{"name":"Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials","volume":"33 1","pages":"214-222"},"PeriodicalIF":0.0,"publicationDate":"2022-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83176756","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 : 2022-03-16DOI: 10.1107/s2052520622001305
I. Collings, M. Hanfland
The high-pressure phase-transition behaviour of metal-organic frameworks and coordination polymers upon varying degrees of X-ray irradiation are highlighted with four example studies. These show that, in certain cases, the radiation damage, while not extreme in changing unit-cell values, can impact the existence of a phase transition. In particular, pressure-induced phase transitions are suppressed after a certain absorbed dose threshold is reached for the sample. This is thought to be due to partial amorphization and/or defect formation in the sample, hindering the co-operative structural distortions needed for a phase transition. The high-pressure experiments were conducted with several crystals within the sample chamber in order to measure crystals with minimal X-ray irradiation at the highest pressures, which are compared with the crystals measured continuously upon pressure increase. Ways to minimize radiation damage are also discussed within the frame of high-pressure experiments.
{"title":"Effect of synchrotron X-ray radiation damage on phase transitions in coordination polymers at high pressure.","authors":"I. Collings, M. Hanfland","doi":"10.1107/s2052520622001305","DOIUrl":"https://doi.org/10.1107/s2052520622001305","url":null,"abstract":"The high-pressure phase-transition behaviour of metal-organic frameworks and coordination polymers upon varying degrees of X-ray irradiation are highlighted with four example studies. These show that, in certain cases, the radiation damage, while not extreme in changing unit-cell values, can impact the existence of a phase transition. In particular, pressure-induced phase transitions are suppressed after a certain absorbed dose threshold is reached for the sample. This is thought to be due to partial amorphization and/or defect formation in the sample, hindering the co-operative structural distortions needed for a phase transition. The high-pressure experiments were conducted with several crystals within the sample chamber in order to measure crystals with minimal X-ray irradiation at the highest pressures, which are compared with the crystals measured continuously upon pressure increase. Ways to minimize radiation damage are also discussed within the frame of high-pressure experiments.","PeriodicalId":7080,"journal":{"name":"Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials","volume":"44 1","pages":"100-106"},"PeriodicalIF":0.0,"publicationDate":"2022-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81472945","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 : 2022-03-15DOI: 10.1107/s2052520622000889
A. Hasija, Shubham Som, D. Chopra
A total of 14 compounds, one unsubstituted and 13 halogen-substituted phosphoramidates, have been synthesized from unsubstituted and halogenated (fluoro-, difluoro-, chloro-, bromo-, iodo-substituted) aniline and diphenyl phosphoryl chloride to investigate their molecular assembly in solid-state structures. Amongst them, six groups were formed based on similarities in unit-cell dimensions, space group and molecular assembly of the crystal. The analysis reveals that all the crystal structures contain robust N-H...O hydrogen bonds which are the primary building blocks with ancillary interactions such as C-H...O, C-H...π, C-H...F/Cl/Br/I, F...F, F...π, I...π, Br...π, I...O and Br...O. The role of short and directional C-H...O and C-H...π interactions providing significant stabilization to the densely packed crystalline arrangement is discussed. The contribution of these interactions in stabilizing the crystalline assembly was deduced via computing total interaction energy between dimers and the overall lattice energies using the computer programs Crystal Explorer 17.5 and PIXELC, respectively. Additionally, the occurrence of 3D isostructurality in phosphoradimates and their halogenated analogs was investigated using the XPac program. A comparison of the magnitudes of the torsion angles in the compounds substantiates the role of conformational flexibility in the solid state.
以未取代苯胺和卤化苯胺(氟、二氟、氯、溴、碘取代)和二苯基磷酸氯为原料合成了14个化合物，其中1个为未取代的，13个为卤素取代的磷酸酰胺，研究了它们在固态结构中的分子组装。其中6个基团是基于晶体的单胞尺寸、空间基团和分子组装的相似性而形成的。分析表明，所有的晶体结构都含有稳定的N-H…O氢键是辅助相互作用的主要组成部分，如碳氢键…O,碳氢键……π,碳氢键……/ Cl / Br /我,F……F, F……π,我…π,Br……π,我…O和Br…O。短而定向的C-H…O和碳氢键…π相互作用提供了显著的稳定密集排列的晶体讨论。通过使用计算机程序Crystal Explorer 17.5和PIXELC分别计算二聚体之间的总相互作用能和总晶格能，推导出这些相互作用对稳定晶体组装的贡献。此外，利用XPac程序研究了磷酸二酸酯及其卤化类似物的三维同构性。化合物中扭角大小的比较证实了构象柔韧性在固态中的作用。
{"title":"Investigation of crystal structures, energetics and isostructurality in halogen-substituted phosphoramidates.","authors":"A. Hasija, Shubham Som, D. Chopra","doi":"10.1107/s2052520622000889","DOIUrl":"https://doi.org/10.1107/s2052520622000889","url":null,"abstract":"A total of 14 compounds, one unsubstituted and 13 halogen-substituted phosphoramidates, have been synthesized from unsubstituted and halogenated (fluoro-, difluoro-, chloro-, bromo-, iodo-substituted) aniline and diphenyl phosphoryl chloride to investigate their molecular assembly in solid-state structures. Amongst them, six groups were formed based on similarities in unit-cell dimensions, space group and molecular assembly of the crystal. The analysis reveals that all the crystal structures contain robust N-H...O hydrogen bonds which are the primary building blocks with ancillary interactions such as C-H...O, C-H...π, C-H...F/Cl/Br/I, F...F, F...π, I...π, Br...π, I...O and Br...O. The role of short and directional C-H...O and C-H...π interactions providing significant stabilization to the densely packed crystalline arrangement is discussed. The contribution of these interactions in stabilizing the crystalline assembly was deduced via computing total interaction energy between dimers and the overall lattice energies using the computer programs Crystal Explorer 17.5 and PIXELC, respectively. Additionally, the occurrence of 3D isostructurality in phosphoradimates and their halogenated analogs was investigated using the XPac program. A comparison of the magnitudes of the torsion angles in the compounds substantiates the role of conformational flexibility in the solid state.","PeriodicalId":7080,"journal":{"name":"Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials","volume":"252 1","pages":"179-194"},"PeriodicalIF":0.0,"publicationDate":"2022-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78197682","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 : 2022-03-15DOI: 10.1107/S205252062200124X
V. Pomjakushin, J. Perez-Mato, P. Fischer, L. Keller, W. Sikora
The antiferromagnetic structure of Tb14Ag51 with the propagation vector [1/3, 1/3, 0] and the parent space group P6/m is revisited using both magnetic symmetry and irreducible representation arguments. A new magnetic structure under the hexagonal Shubnikov magnetic space group P6' which fits much better the experimental data is found. This new solution was obtained by constraining the spin arrangement to one of the three possible magnetic space groups of maximal symmetry that can be realized by a magnetic ordering transforming according to the four-dimensional physically irreducible representation that is known to be relevant in this magnetic phase. The refined model, parameterized under P6', implicitly includes the presence of a third harmonic with the propagation vector at the gamma point [0, 0, 0], which has an important weight in the final result. The structure consists of 13 symmetry-independent Tb magnetic moments with the same size of 8.48 (2) μB, propagating cycloidally in the ab plane. The modulation has a substantial deviation from being purely sinusoidal due to the contribution of the mentioned third harmonic.
{"title":"Revisiting the antiferromagnetic structure of Tb14Ag51: the importance of distinguishing alternative symmetries for a multidimensional order parameter.","authors":"V. Pomjakushin, J. Perez-Mato, P. Fischer, L. Keller, W. Sikora","doi":"10.1107/S205252062200124X","DOIUrl":"https://doi.org/10.1107/S205252062200124X","url":null,"abstract":"The antiferromagnetic structure of Tb14Ag51 with the propagation vector [1/3, 1/3, 0] and the parent space group P6/m is revisited using both magnetic symmetry and irreducible representation arguments. A new magnetic structure under the hexagonal Shubnikov magnetic space group P6' which fits much better the experimental data is found. This new solution was obtained by constraining the spin arrangement to one of the three possible magnetic space groups of maximal symmetry that can be realized by a magnetic ordering transforming according to the four-dimensional physically irreducible representation that is known to be relevant in this magnetic phase. The refined model, parameterized under P6', implicitly includes the presence of a third harmonic with the propagation vector at the gamma point [0, 0, 0], which has an important weight in the final result. The structure consists of 13 symmetry-independent Tb magnetic moments with the same size of 8.48 (2) μB, propagating cycloidally in the ab plane. The modulation has a substantial deviation from being purely sinusoidal due to the contribution of the mentioned third harmonic.","PeriodicalId":7080,"journal":{"name":"Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials","volume":"102 1","pages":"172-178"},"PeriodicalIF":0.0,"publicationDate":"2022-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85114961","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}
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