Pub Date : 2022-09-30DOI: 10.1107/s2052520622009350
V. Young
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.
Brock(2022)的文章是一个雄心勃勃的3年多的项目的结果，该项目旨在研究空间群p1中近似对称性的出现。Brock选择了2019年11月版本的剑桥结构数据库(CSD;Groom等人，2016)，其中发现了2592份有机晶体结构报告(基于Z, z0和R值(cid:2) 0.05)。使用一些标准，该集合被提炼到1407 Z = z0 > 1和1049 Z = z0 = 1。在前一组中，不对称单元内的分子(包括阳离子和阴离子)被评估为可能的近似对称性:2,2,1,3,31，平移，反转或滑动。如果在分子内检测到一些可能的近似对称性，则保留后一组中的条目。如果对称性表明在更高对称性的空间群中可以更好地描述晶体结构的子集，则从两个集合中移除。布洛克的结论是近似对称性在p1晶体结构中普遍存在。
{"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}
Pub Date : 2022-09-10DOI: 10.1107/s2052520622008095
Mimiko Matsuura, H. Okudera
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.
{"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}
Pub Date : 2022-09-09DOI: 10.1107/s2052520622008344
M. Hušák, Simona Šajbanová, J. Klimeš, A. Jegorov
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 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.
{"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}
Pub Date : 2022-09-09DOI: 10.1107/s205252062200779x
D. Brey, Barbara Scherer, M. Schmidt
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.
{"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}
Pub Date : 2022-09-01DOI: 10.1107/s2052520622008289
N. Bogdanov, D. Korabel'nikov, I. Fedorov, B. Zakharov, E. Boldyreva
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.
{"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}
Pub Date : 2022-08-31DOI: 10.1107/s2052520622008150
Arianna C. Ragusa, Andrew J. Peloquin, Marjan M. Shahani, Keri N. Dowling, J. Golen, C. McMillen, D. Rabinovich, W. Pennington
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.
{"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}
Pub Date : 2022-08-19DOI: 10.1107/s2052520622007326
S. Papadopoulou, Fotios Tsiolis, E. Gavalas, S. Papaefthymiou
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.
{"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}
Pub Date : 2022-08-18DOI: 10.1107/S2052520622007375
B. Stöger, E. Peresypkina, A. Virovets
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.
1,3-二(叔丁基)环戊二烯基五磷二茂铁(Cp " FeP5)的扩散散射用生长模型(相互作用范围(reichweite) s = 2)导出的封闭表达式来模拟。
{"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}
Pub Date : 2022-08-16DOI: 10.1107/S2052520622007387
Doan Thi Kieu Anh, Luong Viet Mui, P. H. Minh, N. T. Binh, M. Cadatal-Raduban
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.
{"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}
Pub Date : 2022-07-20DOI: 10.1107/s2052520622007302
Massimo Nespolo
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)
{"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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：