{"title":"Cementitious Materials Science. Theories and Applications. Edited by Lin Zongshou, Xing Weihong and Chen Wei. De Gruyter, 2019. XIII + pp. 403, Paperback. Price EUR 68.95. ISBN 978-3-11-057209-4","authors":"J. Provis","doi":"10.1107/S2052520621000500","DOIUrl":"https://doi.org/10.1107/S2052520621000500","url":null,"abstract":"","PeriodicalId":6887,"journal":{"name":"Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry","volume":"88 1","pages":"182-183"},"PeriodicalIF":0.0,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76513926","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}
{"title":"Polymorphism in Molecular Crystals. Second Edition. By Joel Bernstein. Oxford University Press, 2020, Pp. 608, Hardcover. Price GBP 85.00. ISBN 9780199655441","authors":"C. Lecomte","doi":"10.1107/S2052520621000494","DOIUrl":"https://doi.org/10.1107/S2052520621000494","url":null,"abstract":"","PeriodicalId":6887,"journal":{"name":"Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry","volume":"1 1","pages":"184-185"},"PeriodicalIF":0.0,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78584687","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}
The influence of a disorder in cation substructure on proton conductivity of imidazolium malonate (Im-MAL) is studied. Imidazolium in salts with dicarboxylic acids have been found to have a well ordered hydrogen-bond network and only in Im-MAL [Pogorzelec-Glaser et al. (2006). Mater. Sci.-Pol. (2006), 24, 245–252] were two types of cation observed: ordered Im-I and disordered Im-II. Im-I is involved in hydrogen bonds with malonic acid molecules, whereas Im-II is disordered between two symmetrically equivalent positions with occupancy of 0.5. NMR studies by Mizuno et al. [Hyperfine Interact. (2015), 230, 95–100] showed an 180° flip of ordered Im-I and calculated contribution of Im-I flipping to proton conductivity of Im-MAL. Ławniczak et al. [Solid State Ionics (2017), 306, 25] reported that temperature variation of the proton conductivity by impedance spectroscopy yielded the conductivity value higher than that calculated by Mizuno for Im-I. Moreover these detailed structure studies at 240 K and 280 K excluded any phase transition. Repeated X-ray studies from 14 K to 360 K show a continuous increase in anisotropic displacement factors. The half-occupied hydrogen bonds linking the Im-II nitrogen atoms with hydroxyl oxygen atoms may be considered as electric dipoles and the interbond proton transfer as dipolar switching. It assumed here a coherent switching at low temperatures and a decrease of the coupling at higher temperatures with the disappearance at cross-over temperature at 318 K. The possible proton pathway in the crystal structure is determined and the contribution of the proton dynamics of Im-II to phonon-assisted proton diffusion in the ordered substructure is estimated.
{"title":"Effect of disordered imidazole substructure on proton dynamics in imidazolium malonic acid salt","authors":"P. Ławniczak, K. Pogorzelec-Glaser, A. Pietraszko, B. Hilczer","doi":"10.1107/S2052520620014365","DOIUrl":"https://doi.org/10.1107/S2052520620014365","url":null,"abstract":"The influence of a disorder in cation substructure on proton conductivity of imidazolium malonate (Im-MAL) is studied. Imidazolium in salts with dicarboxylic acids have been found to have a well ordered hydrogen-bond network and only in Im-MAL [Pogorzelec-Glaser et al. (2006). Mater. Sci.-Pol. (2006), 24, 245–252] were two types of cation observed: ordered Im-I and disordered Im-II. Im-I is involved in hydrogen bonds with malonic acid molecules, whereas Im-II is disordered between two symmetrically equivalent positions with occupancy of 0.5. NMR studies by Mizuno et al. [Hyperfine Interact. (2015), 230, 95–100] showed an 180° flip of ordered Im-I and calculated contribution of Im-I flipping to proton conductivity of Im-MAL. Ławniczak et al. [Solid State Ionics (2017), 306, 25] reported that temperature variation of the proton conductivity by impedance spectroscopy yielded the conductivity value higher than that calculated by Mizuno for Im-I. Moreover these detailed structure studies at 240 K and 280 K excluded any phase transition. Repeated X-ray studies from 14 K to 360 K show a continuous increase in anisotropic displacement factors. The half-occupied hydrogen bonds linking the Im-II nitrogen atoms with hydroxyl oxygen atoms may be considered as electric dipoles and the interbond proton transfer as dipolar switching. It assumed here a coherent switching at low temperatures and a decrease of the coupling at higher temperatures with the disappearance at cross-over temperature at 318 K. The possible proton pathway in the crystal structure is determined and the contribution of the proton dynamics of Im-II to phonon-assisted proton diffusion in the ordered substructure is estimated.","PeriodicalId":6887,"journal":{"name":"Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry","volume":"3 1","pages":"31-40"},"PeriodicalIF":0.0,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85234728","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}
Exploiting the kinetic domain provided by hydrothermal conditions, it was possible to isolate three transient metastable crystal structures, each bearing concomitant pairs of octamolybdate isomers, namely, α–β, γ–β or βcs–βgp stabilized by distinctive homoleptic [Co(bpy)3]n+ (bpy = 2,2′-bipyridine; n = 2 or 3) cations generated in situ: [Co(bpy)3]4[(α-Mo8O26)(β-Mo8O26)]·5H2O (1), [NH4][Co(bpy)3][(γ-Mo8O26)0.5(β-Mo8O26)0.5]·4H2O (2) and [Co(bpy)3]2[(βcs-Mo8O26)0.5(βgp-Mo8O26)]·12H2O (3). Solid 1 with the space group P21/n and unit-cell parameters a = 22.160 (6), b = 14.209 (3), c = 24.641 (4) A, β = 99.10 (2)° and V = 7661 (3) A3 resulted in the same crystal structure as that synthesized previously under different conditions by Sun et al. [J. Mol. Struct. (2005), 741, 149–153]. Factors directing the reaction, such as product composition and phase stability, were monitored by analysis of the PXRD patterns of the bulk solids obtained under different experimental conditions. The relative proportions of the mixed phases 1–3 or their stabilization are highly dependent on the initial Co:Mo molar ratio and the reaction temperature. In particular, an increase in temperature induces the transformation of 1–3 into more thermodynamically stable phases formed by one-dimensional coordination polymers [Co(bpy)2(β-Mo8O26)0.5]n (4) and [(MoO3)(bpy)]n (5). The crystal structures of 1–3 correspond to molecular salts self-assembled by C—H⋯O—Mo, C⋯H and H⋯H intermolecular contacts. A Hirshfeld surface analysis for 1 showed that the C⋯H and H⋯H interactions represent an average of 51.8% of the total cation–cation intermolecular contacts. In contrast, these interactions are vastly reduced in 2 (23.0%) and 3 (average 28.5% for both isomers). EPR experiments indicated that the crystal structures of 1 and 3 are paramagnetic, and that for 2 is diamagnetic. The paramagnetism of 3 stems from the in situ formation of [Co(bpy)3]3+ in a high-spin configuration. The structure-directing properties of the [Co(bpy)3]n+ cations in the isolation and self-assembly of concomitant octamolybdate isomers are also described from the viewpoint of crystal engineering.
{"title":"Concomitance of octamolybdate isomers in metastable crystal structures isolated using homoleptic CoII/CoIII complexes as structure-directing templates","authors":"R. Atencio, A. Briceño, J. Bruno-Colmenarez, P. Silva, L. Rodríguez, E. Sosa, Erick Limones, Yesenia Pacheco, Julio Cáceres, Joel E. Vielma","doi":"10.1107/S2052520620015905","DOIUrl":"https://doi.org/10.1107/S2052520620015905","url":null,"abstract":"Exploiting the kinetic domain provided by hydrothermal conditions, it was possible to isolate three transient metastable crystal structures, each bearing concomitant pairs of octamolybdate isomers, namely, α–β, γ–β or βcs–βgp stabilized by distinctive homoleptic [Co(bpy)3]n+ (bpy = 2,2′-bipyridine; n = 2 or 3) cations generated in situ: [Co(bpy)3]4[(α-Mo8O26)(β-Mo8O26)]·5H2O (1), [NH4][Co(bpy)3][(γ-Mo8O26)0.5(β-Mo8O26)0.5]·4H2O (2) and [Co(bpy)3]2[(βcs-Mo8O26)0.5(βgp-Mo8O26)]·12H2O (3). Solid 1 with the space group P21/n and unit-cell parameters a = 22.160 (6), b = 14.209 (3), c = 24.641 (4) A, β = 99.10 (2)° and V = 7661 (3) A3 resulted in the same crystal structure as that synthesized previously under different conditions by Sun et al. [J. Mol. Struct. (2005), 741, 149–153]. Factors directing the reaction, such as product composition and phase stability, were monitored by analysis of the PXRD patterns of the bulk solids obtained under different experimental conditions. The relative proportions of the mixed phases 1–3 or their stabilization are highly dependent on the initial Co:Mo molar ratio and the reaction temperature. In particular, an increase in temperature induces the transformation of 1–3 into more thermodynamically stable phases formed by one-dimensional coordination polymers [Co(bpy)2(β-Mo8O26)0.5]n (4) and [(MoO3)(bpy)]n (5). The crystal structures of 1–3 correspond to molecular salts self-assembled by C—H⋯O—Mo, C⋯H and H⋯H intermolecular contacts. A Hirshfeld surface analysis for 1 showed that the C⋯H and H⋯H interactions represent an average of 51.8% of the total cation–cation intermolecular contacts. In contrast, these interactions are vastly reduced in 2 (23.0%) and 3 (average 28.5% for both isomers). EPR experiments indicated that the crystal structures of 1 and 3 are paramagnetic, and that for 2 is diamagnetic. The paramagnetism of 3 stems from the in situ formation of [Co(bpy)3]3+ in a high-spin configuration. The structure-directing properties of the [Co(bpy)3]n+ cations in the isolation and self-assembly of concomitant octamolybdate isomers are also described from the viewpoint of crystal engineering.","PeriodicalId":6887,"journal":{"name":"Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry","volume":"1 1","pages":"99-114"},"PeriodicalIF":0.0,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86504795","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}
Hexanitrostilbene (HNS) is an energetic material with wide application and excellent comprehensive performance. cis-HNS is successfully prepared using crude HNS with a purity of 95% as the raw material and N-methyl pyrrolidone (NMP) as the solvent. After separation and purification, acetone is used as a solvent to obtain light-yellow crystals at room temperature. The molecular structure of cis-HNS is determined through analysis of Fourier transform infrared, 13C NMR and 1H NMR spectroscopy and single-crystal X-ray diffraction data. The thermal decomposition properties of cis and trans-HNS are studied using differential scanning calorimetry (DSC). When the heating rate is low, cis-HNS will undergo a crystal transformation after melting, from liquid cis-HNS to liquid trans-HNS, and then it will solidify and release heat. According to the results of DSC data, the apparent kinetic parameters of thermal decomposition of cis- and trans-HNS were obtained by Kissinger method [Kissinger (1957). Anal. Chem. 29, 1702–1706] and Ozawa method [Ozawa (1965). Bull. Chem. Soc. Jpn. 38, 1881–1886], respectively. The spontaneous combustion temperature and self-accelerating decomposition temperature of cis and trans-HNS are calculated by the Zhang-Hu-Xie-Li method [Zhang et al. (1994). Thermochim. Acta, 244, 171–176].
己硝基二苯乙烯(HNS)是一种应用广泛、综合性能优异的含能材料。以纯度为95%的粗HNS为原料，n -甲基吡咯烷酮(NMP)为溶剂，成功制备了顺式HNS。分离纯化后，以丙酮为溶剂，在室温下得到淡黄色晶体。通过傅里叶变换红外、13C核磁共振和1H核磁共振波谱以及单晶x射线衍射数据分析，确定了顺式hns的分子结构。用差示扫描量热法(DSC)研究了顺式和反式hns的热分解性质。当加热速率较低时，顺式hns熔化后发生结晶转变，由液态顺式hns变为液态反式hns，然后凝固放热。根据DSC数据，采用Kissinger法得到顺式和反式hns的热分解表观动力学参数[Kissinger(1957)]。分析的化学29,1702-1706]和Ozawa方法[Ozawa(1965)]。公牛。化学。Soc。[j] .中国科学院学报，1881-1886。顺式和反式hns的自燃温度和自加速分解温度采用Zhang- hu - xie - li方法计算[Zhang et al.(1994)]。Thermochim。学报，244,171-176]。
{"title":"The crystal structure and thermal decomposition kinetics of cis-hexanitrostilbene","authors":"Yun-Zhu Liu, Lizhen Chen, Jianlong Wang, Jun Chen, Jingqi Wang, Hongxia Pan","doi":"10.1107/S2052520620015371","DOIUrl":"https://doi.org/10.1107/S2052520620015371","url":null,"abstract":"Hexanitrostilbene (HNS) is an energetic material with wide application and excellent comprehensive performance. cis-HNS is successfully prepared using crude HNS with a purity of 95% as the raw material and N-methyl pyrrolidone (NMP) as the solvent. After separation and purification, acetone is used as a solvent to obtain light-yellow crystals at room temperature. The molecular structure of cis-HNS is determined through analysis of Fourier transform infrared, 13C NMR and 1H NMR spectroscopy and single-crystal X-ray diffraction data. The thermal decomposition properties of cis and trans-HNS are studied using differential scanning calorimetry (DSC). When the heating rate is low, cis-HNS will undergo a crystal transformation after melting, from liquid cis-HNS to liquid trans-HNS, and then it will solidify and release heat. According to the results of DSC data, the apparent kinetic parameters of thermal decomposition of cis- and trans-HNS were obtained by Kissinger method [Kissinger (1957). Anal. Chem. \u0000 29, 1702–1706] and Ozawa method [Ozawa (1965). Bull. Chem. Soc. Jpn. \u0000 38, 1881–1886], respectively. The spontaneous combustion temperature and self-accelerating decomposition temperature of cis and trans-HNS are calculated by the Zhang-Hu-Xie-Li method [Zhang et al. (1994). Thermochim. Acta, 244, 171–176].","PeriodicalId":6887,"journal":{"name":"Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry","volume":"44 1","pages":"150-157"},"PeriodicalIF":0.0,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86626820","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}
Three novel multinuclear NiII complexes, namely, bis{μ-2-methoxy-6-[8-(pyridin-2-yl)-3,6-dioxa-2,7-diazaocta-1,7-dien-1-yl]phenolato}bis[thiocyanatonickel(II)], [Ni2(L)2(NCS)2], 1, bis{μ-2-methoxy-6-[8-(pyridin-2-yl)-3,6-dioxa-2,7-diazaocta-1,7-dien-1-yl]phenolato}bis[azidonickel(II)], [Ni2(L)2(N3)2], 2, and catena-poly[[{2-methoxy-6-[8-(pyridin-2-yl)-3,6-dioxa-2,7-diazaocta-1,7-dien-1-yl]phenolato}nickel(II)]-μ-dicyanamidato], [Ni(L)(dca)] n , 3 {dca is dicyanamide, C2N3, and HL is 2-methoxy-6-[8-(pyridin-2-yl)-3,6-dioxa-2,7-diazaocta-1,7-dien-1-yl]phenol, C16H17N3O4}, with a half-salamo-based pyridine-containing HL ligand have been synthesized and characterized by FT–IR, UV–Vis absorption spectroscopy, X-ray crystallography, Hirshfeld surface analysis and density functional theory (DFT) calculations. The central NiII ions in complexes 1–3 are hosted in the half-salamo-based N3O-donor cavity of the organic ligand. Complex 1 is a centrosymmetric dimer and two [Ni(L)(NCS)] units form a centrosymmetric dimeric structure, which is bridged by two phenolate O atoms. The two N atoms at the axial ends are provided by two NCS− ligands. In complex 1, each NiII ion has a six-coordinated octahedral geometry. Complex 2 is similar to 1, but they differ in that the auxiliary NCS− ligand is replaced by N3 −. However, complex 3 is a one-dimensional coordination polymer constructed from [Ni(L)(dca)] units, which are connected by the auxiliary bidentate dca ligand via N-donor atoms. As with complexes 1 and 2, the NiII ion in 3 has a six-coordinated octahedral geometry.
{"title":"A half-salamo-based pyridine-containing ligand and its novel NiII complexes including different auxiliary ligands: syntheses, structures, fluorescence properties, DFT calculations and Hirshfeld surface analysis","authors":"T. Feng, Li‐Li Li, Ya-Juan Li, W. Dong","doi":"10.1107/S2052520620016157","DOIUrl":"https://doi.org/10.1107/S2052520620016157","url":null,"abstract":"Three novel multinuclear NiII complexes, namely, bis{μ-2-methoxy-6-[8-(pyridin-2-yl)-3,6-dioxa-2,7-diazaocta-1,7-dien-1-yl]phenolato}bis[thiocyanatonickel(II)], [Ni2(L)2(NCS)2], 1, bis{μ-2-methoxy-6-[8-(pyridin-2-yl)-3,6-dioxa-2,7-diazaocta-1,7-dien-1-yl]phenolato}bis[azidonickel(II)], [Ni2(L)2(N3)2], 2, and catena-poly[[{2-methoxy-6-[8-(pyridin-2-yl)-3,6-dioxa-2,7-diazaocta-1,7-dien-1-yl]phenolato}nickel(II)]-μ-dicyanamidato], [Ni(L)(dca)]\u0000 n\u0000 , 3 {dca is dicyanamide, C2N3, and HL is 2-methoxy-6-[8-(pyridin-2-yl)-3,6-dioxa-2,7-diazaocta-1,7-dien-1-yl]phenol, C16H17N3O4}, with a half-salamo-based pyridine-containing HL ligand have been synthesized and characterized by FT–IR, UV–Vis absorption spectroscopy, X-ray crystallography, Hirshfeld surface analysis and density functional theory (DFT) calculations. The central NiII ions in complexes 1–3 are hosted in the half-salamo-based N3O-donor cavity of the organic ligand. Complex 1 is a centrosymmetric dimer and two [Ni(L)(NCS)] units form a centrosymmetric dimeric structure, which is bridged by two phenolate O atoms. The two N atoms at the axial ends are provided by two NCS− ligands. In complex 1, each NiII ion has a six-coordinated octahedral geometry. Complex 2 is similar to 1, but they differ in that the auxiliary NCS− ligand is replaced by N3\u0000 −. However, complex 3 is a one-dimensional coordination polymer constructed from [Ni(L)(dca)] units, which are connected by the auxiliary bidentate dca ligand via \u0000 N-donor atoms. As with complexes 1 and 2, the NiII ion in 3 has a six-coordinated octahedral geometry.","PeriodicalId":6887,"journal":{"name":"Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry","volume":"51 1","pages":"168-181"},"PeriodicalIF":0.0,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83603536","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}
The Independent Atom Model (IAM) of electron density is used in routine X-ray data analysis. However, this model does not give a quantitative description of the electron-density distribution. A better model that allows for modelling of aspherical charge density deformations is introduced by the Hansen–Coppens variant of the multipole model of electron density. However, the application of this model requires crystals of excellent quality and high-resolution XRD data which are quite often difficult criteria to fulfil. Therefore, Mo Kα and Cu Kα data of three model compounds (tricyclic imide, xylitol and methyluracil) were refined using IAM and new methods which enabled the refinement and reconstruction of charge density based on the Cu Kα data. These methods were the Bond-Oriented Deformation Density (BODD) model, Hirshfeld Atom Refinement (HAR) and the Transferable Aspherical Atom Model (TAAM). The final results were compared to the model obtained from neutron diffraction experiments. Our results demonstrated not only that Cu Kα data may be refined using BODD, HAR and TAAM methods, but also revealed systematic errors arising from the use of Cu Kα data. These errors were a result of the limited information in the low-resolution data set that manifested as higher values for the anisotropic displacement parameters (ADPs) and smaller maxima and minima of the residual electron density for the Cu Kα data compared to the Mo Kα data. Notably, these systematic errors were much less significant than those found for the IAM. Therefore, the application of BODD, HAR and TAAM on Cu Kα data has a more significant influence on the final results of refinement than for the Mo Kα data.
{"title":"HAR, TAAM and BODD refinements of model crystal structures using Cu Kα and Mo Kα X-ray diffraction data","authors":"Monika Wanat, M. Malińska, M. Gutmann, R. Cooper, K. Woźniak","doi":"10.1107/S2052520620014936","DOIUrl":"https://doi.org/10.1107/S2052520620014936","url":null,"abstract":"The Independent Atom Model (IAM) of electron density is used in routine X-ray data analysis. However, this model does not give a quantitative description of the electron-density distribution. A better model that allows for modelling of aspherical charge density deformations is introduced by the Hansen–Coppens variant of the multipole model of electron density. However, the application of this model requires crystals of excellent quality and high-resolution XRD data which are quite often difficult criteria to fulfil. Therefore, Mo Kα and Cu Kα data of three model compounds (tricyclic imide, xylitol and methyluracil) were refined using IAM and new methods which enabled the refinement and reconstruction of charge density based on the Cu Kα data. These methods were the Bond-Oriented Deformation Density (BODD) model, Hirshfeld Atom Refinement (HAR) and the Transferable Aspherical Atom Model (TAAM). The final results were compared to the model obtained from neutron diffraction experiments. Our results demonstrated not only that Cu Kα data may be refined using BODD, HAR and TAAM methods, but also revealed systematic errors arising from the use of Cu Kα data. These errors were a result of the limited information in the low-resolution data set that manifested as higher values for the anisotropic displacement parameters (ADPs) and smaller maxima and minima of the residual electron density for the Cu Kα data compared to the Mo Kα data. Notably, these systematic errors were much less significant than those found for the IAM. Therefore, the application of BODD, HAR and TAAM on Cu Kα data has a more significant influence on the final results of refinement than for the Mo Kα data.","PeriodicalId":6887,"journal":{"name":"Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry","volume":"5 1","pages":"41-53"},"PeriodicalIF":0.0,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90416566","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}
Almost 50 years after the initial report, the crystal structure of Cu2GeSe3, a I2-IV-VI3 semiconductor, has been revised using modern single-crystal X-ray diffraction data. The structure of this material can be properly described in the monoclinic space group Cc (No. 9) with unit-cell parameters a = 6.7703 (4) Å, b = 11.8624 (5) Å, c = 6.7705 (4) Å, β = 108.512 (6)°, V = 515.62 (5) Å3, Z = 4, rather than in the orthorhombic space group Imm2 (No. 44) with unit-cell parameters a = 11.860 (3), b = 3.960 (1), c = 5.485 (2) Å, V = 257.61 Å3, Z = 2, as originally proposed [Parthé & Garín (1971). Monatsh. Chem. 102, 1197–1208]. Contrary to what was observed in the orthorhombic structure, the distortions of the tetrahedra in the monoclinic structure are consistent with the distortions expected from considerations derived from the bond valence model. A brief revision of the structures reported for the I2-IV-VI3 family of semiconducting compounds (I: Cu, Ag; IV: Si, Ge, Sn; and VI: S, Se, Te) is also presented.
在最初的报告发表近50年后，利用现代单晶x射线衍射数据对I2-IV-VI3半导体Cu2GeSe3的晶体结构进行了修正。这种材料的结构可以正确描述的单斜晶体的空间群Cc(9号)与晶胞参数= 6.7703 (4)a, b = 11.8624 (5) a, c = 6.7705(4),β= 108.512(6)°,V = 515.62 (5) A3, Z = 4,而不是在斜方晶系的空间群Imm2(44)与晶胞参数= 11.860 (3),b = 3.960 (1), c = 5.485 (2), V = 257.61 A3, Z = 2,最初提议(帕尔丝&加林(1971)。Monatsh。化学通报，1999,19(2):1 - 8。与在正交结构中观察到的相反，单斜结构中四面体的畸变与从键价模型中推导出的畸变一致。对I2-IV-VI3家族半导体化合物(I: Cu, Ag;IV: Si, Ge, Sn;以及VI: S, Se, Te)。
{"title":"The crystal structure of Cu2GeSe3 and the structure-types of the I2-IV-VI3 family of semiconducting compounds","authors":"Analio Dugarte-Dugarte, Nahum Ramírez Pineda, L. Nieves, J. Henao, G. C. Diaz de Delgado, J. M. Delgado","doi":"10.1107/S2052520620016571","DOIUrl":"https://doi.org/10.1107/S2052520620016571","url":null,"abstract":"Almost 50 years after the initial report, the crystal structure of Cu2GeSe3, a I2-IV-VI3 semiconductor, has been revised using modern single-crystal X-ray diffraction data. The structure of this material can be properly described in the monoclinic space group Cc (No. 9) with unit-cell parameters a = 6.7703 (4) Å, b = 11.8624 (5) Å, c = 6.7705 (4) Å, β = 108.512 (6)°, V = 515.62 (5) Å3, Z = 4, rather than in the orthorhombic space group Imm2 (No. 44) with unit-cell parameters a = 11.860 (3), b = 3.960 (1), c = 5.485 (2) Å, V = 257.61 Å3, Z = 2, as originally proposed [Parthé & Garín (1971). Monatsh. Chem. \u0000 102, 1197–1208]. Contrary to what was observed in the orthorhombic structure, the distortions of the tetrahedra in the monoclinic structure are consistent with the distortions expected from considerations derived from the bond valence model. A brief revision of the structures reported for the I2-IV-VI3 family of semiconducting compounds (I: Cu, Ag; IV: Si, Ge, Sn; and VI: S, Se, Te) is also presented.","PeriodicalId":6887,"journal":{"name":"Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry","volume":"3 3 1","pages":"158-167"},"PeriodicalIF":0.0,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83642236","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}
SB IPHYS LPMC, EPFL, Bâtiment PH Station 3, Lausanne, CH-1015, Switzerland, Phase Solutions Ltd, Ch. des Mésanges 7, Lausanne, CH-1015, Switzerland, SNBL, ESRF, 71 Avenue des Martyrs, Cedex 9, Grenoble, 38043, France, SB IPHYS LQM, EPFL, Bâtiment PH Station 3, Lausanne, CH-1015, Switzerland, SB IPHYS BSP/Cubotron, EPFL, Lausanne, CH-1015, Switzerland, Department of Physics, Faculty of Science, University of Zagreb, Zagreb, HR-100000, Croatia, and Institute of Solid State Physics, TU Wien, Vienna, 1040, Austria. *Correspondence e-mail: alla.arakcheeva@epfl.ch
SB IPHYS LPMC, EPFL, b timent PH站3，洛桑，CH-1015，瑞士，洛桑，CH-1015，瑞士，洛桑，CH-1015, Cedex 9，法国，格勒诺布尔，38043，法国，烈士大道71号，SNBL, ESRF, SB IPHYS LQM, EPFL, b timent PH站3，洛桑，CH-1015，瑞士，洛桑，CH-1015，瑞士，萨格勒布，hr100000，克罗地亚，萨格勒布，萨格勒布，科学学院物理系，SB IPHYS BSP/Cubotron, EPFL，洛桑，CH-1015，和维也纳理工大学固体物理研究所，维也纳，1040年，奥地利*通信邮箱:alla.arakcheeva@epfl.ch
{"title":"One-dimensional composite host–guest structure in BaVS3","authors":"A. Arakcheeva, P. Pattison, G. Chapuis, H. Berger, N. Barišić, L. Forró","doi":"10.1107/S2052520620016108","DOIUrl":"https://doi.org/10.1107/S2052520620016108","url":null,"abstract":"SB IPHYS LPMC, EPFL, Bâtiment PH Station 3, Lausanne, CH-1015, Switzerland, Phase Solutions Ltd, Ch. des Mésanges 7, Lausanne, CH-1015, Switzerland, SNBL, ESRF, 71 Avenue des Martyrs, Cedex 9, Grenoble, 38043, France, SB IPHYS LQM, EPFL, Bâtiment PH Station 3, Lausanne, CH-1015, Switzerland, SB IPHYS BSP/Cubotron, EPFL, Lausanne, CH-1015, Switzerland, Department of Physics, Faculty of Science, University of Zagreb, Zagreb, HR-100000, Croatia, and Institute of Solid State Physics, TU Wien, Vienna, 1040, Austria. *Correspondence e-mail: alla.arakcheeva@epfl.ch","PeriodicalId":6887,"journal":{"name":"Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry","volume":"1 1","pages":"115-122"},"PeriodicalIF":0.0,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90374884","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}
The structures of the plastic crystal (PC), orientational glass (OTG), liquid (LQ) and ordinary glass (OG) phases of 1,6-anhydro-β-D-glucopyranose (levoglucosan) have been investigated using X-ray diffraction and molecular modeling. The experimental diffraction data in the forms of static structure factors and pair distribution functions are analyzed in reciprocal and real spaces and compared with results of model-based simulations. A new approach to modeling the structure of the disordered phases, taking into account the intermolecular scattering contribution in the form of sharp Bragg peaks, the slowly varying intensity associated with intramolecular correlations and the diffusive component resulting from structural disorder, is applied. In the case of the LQ and OG samples, reverse Monte Carlo simulations are also used. The PC and OTG phases show long-range ordering of the hexagonal close-packed (hcp)-type structure up to 120 Å with random orientation of the molecules. Assuming a rigid molecular skeleton, isotropic free rotations of the molecules about their geometrical center in full and limited angular ranges are generated in theoretical models of the structure. It is demonstrated that the adoption of free rotations of the molecules leads to the best fits to experimental data for each studied phase of levoglucosan. The diffraction patterns of the LQ and OG samples show a relatively sharp first peak originating from quasi-Bragg planes of the densely packed face-centered cubic (fcc) type molecular arrangement. Moreover, the slowly varied intensity component of LQ and OG is practically the same as that of PC and OTG, suggesting that the intramolecular structure of these four phases does not change. Interestingly, structural correlations for the disordered LQ and OG states extend surprisingly far, up to about 50 Å. In addition, for all levoglucosan phases investigated, the paracrystalline disorder imposed on the generated models resulted in better compliance with the experimental data.
利用x射线衍射和分子模型研究了1,6-无水-β- d -葡萄糖醛酸(左旋葡聚糖)的塑料晶体(PC)、取向玻璃(OTG)、液相(LQ)和普通玻璃(OG)相的结构。以静态结构因子和对分布函数的形式对实验衍射数据在倒数空间和实空间进行了分析，并与基于模型的模拟结果进行了比较。采用了一种新的方法来模拟无序相的结构，该方法考虑了以尖锐布拉格峰形式出现的分子间散射贡献、与分子内相关性相关的缓慢变化强度以及由结构无序引起的扩散成分。在LQ和OG样本的情况下，反向蒙特卡罗模拟也被使用。PC相和OTG相表现出六方密排(hcp)型结构的长程有序，最高可达120 Å，分子取向随机。假设分子骨架是刚性的，在该结构的理论模型中产生了分子围绕其几何中心在完全和有限角度范围内的各向同性自由旋转。结果表明，采用分子的自由旋转导致左旋葡聚糖的每个研究相的实验数据的最佳拟合。LQ和OG样品的衍射图显示出一个相对尖锐的第一峰，它来自于密集排列的面心立方(fcc)型分子排列的准布拉格面。此外，LQ和OG的缓变强度组分与PC和OTG的缓变强度组分基本相同，说明这四相的分子内结构没有发生变化。有趣的是，无序LQ和OG状态的结构相关性出奇地远，高达约50 Å。此外，在所研究的所有左旋葡聚糖相中，对生成的模型施加的准晶无序性导致与实验数据的一致性更好。
{"title":"Structure of 1,6-anhydro-β-D-glucopyranose in plastic crystal, orientational glass, liquid and ordinary glass forms: molecular modeling and X-ray diffraction studies","authors":"K. Jurkiewicz, Wojciech Glajcar, K. Kamiński, L. Temleitner, A. Burian","doi":"10.1107/S205252062001656X","DOIUrl":"https://doi.org/10.1107/S205252062001656X","url":null,"abstract":"The structures of the plastic crystal (PC), orientational glass (OTG), liquid (LQ) and ordinary glass (OG) phases of 1,6-anhydro-β-D-glucopyranose (levoglucosan) have been investigated using X-ray diffraction and molecular modeling. The experimental diffraction data in the forms of static structure factors and pair distribution functions are analyzed in reciprocal and real spaces and compared with results of model-based simulations. A new approach to modeling the structure of the disordered phases, taking into account the intermolecular scattering contribution in the form of sharp Bragg peaks, the slowly varying intensity associated with intramolecular correlations and the diffusive component resulting from structural disorder, is applied. In the case of the LQ and OG samples, reverse Monte Carlo simulations are also used. The PC and OTG phases show long-range ordering of the hexagonal close-packed (hcp)-type structure up to 120 Å with random orientation of the molecules. Assuming a rigid molecular skeleton, isotropic free rotations of the molecules about their geometrical center in full and limited angular ranges are generated in theoretical models of the structure. It is demonstrated that the adoption of free rotations of the molecules leads to the best fits to experimental data for each studied phase of levoglucosan. The diffraction patterns of the LQ and OG samples show a relatively sharp first peak originating from quasi-Bragg planes of the densely packed face-centered cubic (fcc) type molecular arrangement. Moreover, the slowly varied intensity component of LQ and OG is practically the same as that of PC and OTG, suggesting that the intramolecular structure of these four phases does not change. Interestingly, structural correlations for the disordered LQ and OG states extend surprisingly far, up to about 50 Å. In addition, for all levoglucosan phases investigated, the paracrystalline disorder imposed on the generated models resulted in better compliance with the experimental data.","PeriodicalId":6887,"journal":{"name":"Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry","volume":"49 1","pages":"138-149"},"PeriodicalIF":0.0,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79407899","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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