Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials最新文献

{"title":"Learning from approximate periodic symmetry in organic P1 structures","authors":"V. Young","doi":"10.1107/s2052520622009350","DOIUrl":"https://doi.org/10.1107/s2052520622009350","url":null,"abstract":"The article by Brock (2022) is the result of an ambitious 3+ year long project to study the occurrences of approximate symmetries in the space group P 1. Brock selected the November 2019 version of the Cambridge Structural Database (CSD; Groom et al. , 2016) where 2592 reports of organic crystal structures (based on Z , Z 0 and an R value (cid:2) 0.05) were found. Using a number of criteria this set was distilled down to 1407 Z = Z 0 > 1 and 1049 Z = Z 0 = 1. In the former group, molecules (including cations and anions) within asymmetric units were evaluated for possible approximate symmetries: 2, 2 1 , 3, 3 1 , translations, inversions or glides. Entries in the latter group were retained if some possible approximate symmetry was detected within the molecule(s). A subset of crystal structures was removed from both sets if the symmetry indicated these would be better described in a higher-symmetry space group. Brock’s conclusion is that approximate symmetry is pervasive in P 1 crystal structures.","PeriodicalId":7080,"journal":{"name":"Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76185236","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":"Structures of Ca5(VO4)3Cl and Ca4.78(1)Na0.22(PO4)3Cl0.78: positions of channel anions and repulsion on the anion in apatite-type compounds","authors":"Mimiko Matsuura, H. Okudera","doi":"10.1107/s2052520622008095","DOIUrl":"https://doi.org/10.1107/s2052520622008095","url":null,"abstract":"Single crystal specimens of apatite-type compounds Ca5(VO4)3Cl and Ca4.78 (1)Na0.22(PO4)3Cl0.78 were prepared with a flux-growth technique and their structures were examined with single-crystal X-ray diffraction. The anion channel is defined by a face-sharing array of nearly regular Ca octahedra, which run along c, together with flat O3 trigonal antiprisms that are concentric with the Ca octahedra and highly oblate in [001]. The position of the channel anion in Ca5(VO4)3Cl is split into two at [0, 0, ±0.1691 (6)] with half occupancies. Dynamic disorder among these two positions is suggested from a saddle-shaped electron density distribution through the Ca regular triangle, i.e. the shared face of the Ca octahedra at z = ¼. The position of Cl− was too close to Ca2+ under bond-valence consideration. This is due to repulsion on Cl− from the flat O3 trigonal antiprism which is located at z = 0, namely, in between pairs of split Cl site positions. Ca4.78 (1)Na0.22(PO4)3Cl0.78 crystallizes as a disordered hexagonal structure in which the crystallographic pattern is not an intermediate state but a projection of two distinct halves of the monoclinic pattern [doubled in b; Mackie, Elliot & Young (1972). Acta Cryst. B28, 1840–1848] in one hexagonal cell. In spite of quite different environments, the bond-valence sums for Cl− in these structures are large and similar to each other. The repulsion between O2− and Cl− and a demand for keeping Ca2+ and Cl− apart are balanced at the positions where bond-valence sums for Cl− are around 1.2.","PeriodicalId":7080,"journal":{"name":"Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials","volume":"227 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88401928","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":"The potential of dispersion-corrected density functional theory calculations for distinguishing between salts and cocrystals","authors":"M. Hušák, Simona Šajbanová, J. Klimeš, A. Jegorov","doi":"10.1107/s2052520622008344","DOIUrl":"https://doi.org/10.1107/s2052520622008344","url":null,"abstract":"Validation of a method for distinguishing between salts and cocrystals based on dispersion-corrected density functional theory is presented. Existing related works (van de Streek & Neumann, 2010; LeBlanc et al., 2018) indicate that this approach is problematic and leads to incorrect results in multiple situations. The method suggested here is based on the geometry optimization of an artificially constructed wrong structure (hydrogen atom placed in salt position near the potential acceptor for cocrystals and vice versa cocrystal position with hydrogen atom placed near the potential donor of the salts). The verification of the method is based on comparison of the results with an experimentally confirmed correct hydrogen position. Calculations were performed on 173 selected structures of salts and 96 cocrystals with ΔpKa\u0000 in the critical 〈−1, 4〉 range. The range was chosen to test the method on the most problematic structures. When the artificial wrong model did not converge to the correct one (salt to cocrystal and vice versa), it was tested whether the correct model converged to the correct one in addition. The results confirmed that the most widely used functional (PBE) tends to generate false salt results. All salts converged to the salt from cocrystal initial models. Sixteen cocrystals showed local energy minima for both the salt and cocrystal states. Eighteen cocrystals always converged to salt. Rules were identified under which the results can be considered reliable: when a cocrystal starting model converges to cocrystal, the structure is certainly cocrystal. When both the cocrystal and salt models converge to salt for a long hydrogen-bond (longer than 2.613 Å) the structure is most likely salt. For short hydrogen bonds it is not possible to distinguished reliably between salt and cocrystal using the dispersion-corrected PBE functional. Additional calculations were performed with more advanced functionals for 18 problematic structures detected in the screening as well as for four more mentioned in the literature. The results show that the rSCAN functional (Bartók & Yates, 2019) improves the agreement with the experiment. Further improvement was observed by using hybrid functionals (PBE0, PBE50), which were tested on structures that gave incorrect results with rSCAN. The described method for distinguishing salts from cocrystals can be useful for enhancing the information given by structure solutions from powder, the verification of structure solutions from single crystals and studies related to crystal structure prediction.","PeriodicalId":7080,"journal":{"name":"Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83240104","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":"Lattice defects in quinacridone","authors":"D. Brey, Barbara Scherer, M. Schmidt","doi":"10.1107/s205252062200779x","DOIUrl":"https://doi.org/10.1107/s205252062200779x","url":null,"abstract":"Various lattice defects in the αI-phase of quinacridone (C20H12N2O2) were simulated using lattice-energy minimizations, including vacancies, stacking faults, screw and edge dislocations, twinning and orientational faults. Twinning and orientational faults of entire chains were calculated to occur most frequently.","PeriodicalId":7080,"journal":{"name":"Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials","volume":"9 1","pages":"763 - 780"},"PeriodicalIF":0.0,"publicationDate":"2022-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81532377","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":"The effect of hydrostatic compression on the crystal structure of glycinium phosphite","authors":"N. Bogdanov, D. Korabel'nikov, I. Fedorov, B. Zakharov, E. Boldyreva","doi":"10.1107/s2052520622008289","DOIUrl":"https://doi.org/10.1107/s2052520622008289","url":null,"abstract":"The crystal structure of glycinium phosphite (GPI) was studied in the pressure range from ambient to 6.5 GPa at 293 K using single-crystal X-ray diffraction. The changes in the unit-cell volume and parameters were continuous and anisotropic. The major compression was observed normal to the direction of the spontaneous polarization that occurs in this structure during a ferroelectric phase transition on cooling, whereas the structural compression along the b axis coinciding with the 21 axis was almost zero. The effect of pressure on the hydrogen bonds linking the H2PO3 tetrahedra into zigzag chains along the c axis was different from that on the hydrogen bonds connecting the glycinium cations with the H2PO3 tetrahedra in the (b × c) plane. The discontinuous changes in the geometries of selected hydrogen bonds at about 1.21 GPa may be evidence of a phase transition, e.g. into an ordered ferroelectric phase (with ordered positions of protons). The anisotropy of compression of GPI in the ferroelectric state (at 0 K) was studied using DFT calculations taking into account dispersive van der Waals interactions. The calculations predicted negative linear compressibility along the b axis.","PeriodicalId":7080,"journal":{"name":"Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76616142","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":"Heterocyclic 1,3-diazepine-based thiones and selones as versatile halogen-bond acceptors","authors":"Arianna C. Ragusa, Andrew J. Peloquin, Marjan M. Shahani, Keri N. Dowling, J. Golen, C. McMillen, D. Rabinovich, W. Pennington","doi":"10.1107/s2052520622008150","DOIUrl":"https://doi.org/10.1107/s2052520622008150","url":null,"abstract":"Utilizing the N-heterocyclic chalcogenones hexahydro-1,3-bis(2,4,6-trimethylphenyl)-2H-1,3-diazepine-2-thione (SDiazMesS) and hexahydro-1,3-bis(2,4,6-trimethylphenyl)-2H-1,3-diazepine-2-selone (SDiazMesSe) as halogen-bond acceptors, 24 new cocrystals were prepared. The solid-state structures of the parent molecules were also determined, along with those of their acetonitrile solvates.","PeriodicalId":7080,"journal":{"name":"Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials","volume":"30 1","pages":"745 - 755"},"PeriodicalIF":0.0,"publicationDate":"2022-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75525152","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":"Evolution of microstructure and crystallographic texture throughout the rolling process of AA3104","authors":"S. Papadopoulou, Fotios Tsiolis, E. Gavalas, S. Papaefthymiou","doi":"10.1107/s2052520622007326","DOIUrl":"https://doi.org/10.1107/s2052520622007326","url":null,"abstract":"The metallic components are manufactured through several thermomechanical processes. Each selected procedure has multiple targets. The first target is to obtain the required dimensional criteria and second, to achieve the ideal mechanical response toward the application. This is currently accomplished through years of knowhow combined with an academic background of materials science and engineering. Since metals are polycrystalline materials, the several rotations of the crystals, the preferred orientation also known as texture, and their interactions, are crucial characteristics that are directly correlated to the final response of the material, and one could apprehend its thermomechanical prehistory as well as predict is behavior. Different atomic arrangements act differently texture-wise therefore in the current review article, the evolution of the microstructure and the crystallographic texture through the thermomechanically rolling process especially of Al alloys for packaging applications is analyzed. The crystallographic texture evolution in 3xxx Al alloys in different processing routes is presented and compared to the anisotropic effects occurring during deep drawing. The earing phenomena in Al alloys are correlated to the produced texture and therefore their understanding is crucial in order to highlight the importance of texture control throughout the thermomechanical process.","PeriodicalId":7080,"journal":{"name":"Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials","volume":"104 4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78346970","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":"One-dimensional diffuse scattering of 1,3-di(tert-butyl)cyclopentadienyl pentaphosphaferrocene modelled with closed-form expressions","authors":"B. Stöger, E. Peresypkina, A. Virovets","doi":"10.1107/S2052520622007375","DOIUrl":"https://doi.org/10.1107/S2052520622007375","url":null,"abstract":"The diffuse scattering of 1,3-di(tert-butyl)cyclopentadienyl pentaphosphaferrocene (Cp′′FeP5) is modelled with closed-form expressions derived from a growth model with the range of interactions (reichweite) s = 2.","PeriodicalId":7080,"journal":{"name":"Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials","volume":"114 1","pages":"734 - 744"},"PeriodicalIF":0.0,"publicationDate":"2022-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87619948","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":"Engineering the band gap and optical properties of a two-dimensional molybdenum carbon fluoride MXene","authors":"Doan Thi Kieu Anh, Luong Viet Mui, P. H. Minh, N. T. Binh, M. Cadatal-Raduban","doi":"10.1107/S2052520622007387","DOIUrl":"https://doi.org/10.1107/S2052520622007387","url":null,"abstract":"Using first-principles density functional theory, the electronic and optical properties of monolayer and multilayer nanosheets of molybdenum carbon fluoride (Mo2CF2), a two-dimensional (2D) transition-metal carbide MXene, were investigated. The unique behavior of its optical properties along with the ability to control its electronic and optical properties enhances the potential of 2D Mo2CF2 for various applications in the fields of electronics and energy storage.","PeriodicalId":7080,"journal":{"name":"Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials","volume":"17 1","pages":"714 - 720"},"PeriodicalIF":0.0,"publicationDate":"2022-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84218696","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":"Framboids. By David Rickard. Oxford University Press, 2021. Hardcover, pp. xxv+334. Price GBP 64.00. ISBN ISBN 978019008 0112.","authors":"Massimo Nespolo","doi":"10.1107/s2052520622007302","DOIUrl":"https://doi.org/10.1107/s2052520622007302","url":null,"abstract":"Framboids are microscopic, subspherical aggregates of pyrite microcrystals, where the sulfide is mainly microbiological in origin: a framboid may contain fewer than 100 or more than 500 000 microcrystals. The sizes of the microcrystals span however a much smaller interval. Framboids are ubiquitous but require unique conditions to form. The book by David Rickard, world authority on sulfide chemistry, geochemistry, geomicro-biology, biogeochemistry and ore geology, opens the doors of this fascinating world. The importance of these minuscule aggregates cannot be underestimated, if we consider that pyrite nanoparticles contribute a significant component of the nanoparticulate budget of the oceans [ . . . ] and may contribute up to 10% of the dissolved iron emanating from black smoker hydrothermal vents (page 109)","PeriodicalId":7080,"journal":{"name":"Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials","volume":"25 1","pages":"710-711"},"PeriodicalIF":0.0,"publicationDate":"2022-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89568756","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}