Acta crystallographica Section B, Structural science, crystal engineering and materials最新文献

{"title":"Crystal structure of new quaternary intermetallic compounds R₂MoSi₂C (R = Y, Gd).","authors":"Anne Vernière, Léopold V B Diop, Ibrahima Sarr, Thierry Schweitzer, Bernard Malaman","doi":"10.1107/S2052520624007017","DOIUrl":"10.1107/S2052520624007017","url":null,"abstract":"<p><p>The discovery of novel quaternary intermetallic compounds R₂MoSi₂C (R = Y, Gd) in the R-Mo-Si-C system is reported. Their crystal structure was investigated using single-crystal X-ray diffraction. It is shown that the Y₂MoSi₂C and Gd₂MoSi₂C compounds crystallize in the tetragonal space group P4/mbm (Pearson symbol tP12) with unit-cell parameters a = 6.9525 (18) Å, c = 4.1962 (16) Å, and a = 6.9945 (16) Å, c = 4.2020 (14) Å, respectively.</p>","PeriodicalId":7320,"journal":{"name":"Acta crystallographica Section B, Structural science, crystal engineering and materials","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142339157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A new Section Editor for Acta Cryst. B.","authors":"Louise N Dawe, Ashwini Nangia","doi":"10.1107/S2052520624009041","DOIUrl":"https://doi.org/10.1107/S2052520624009041","url":null,"abstract":"<p><p>Introducing the new Section Editor for Acta Cryst. B.</p>","PeriodicalId":7320,"journal":{"name":"Acta crystallographica Section B, Structural science, crystal engineering and materials","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142455735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Importance of powder diffraction raw data archival in a curated database for materials science applications.","authors":"Soorya Kabekkodu, Thomas Blanton","doi":"10.1107/S2052520624006607","DOIUrl":"10.1107/S2052520624006607","url":null,"abstract":"<p><p>In recent years, there is a significant interest from the crystallographic and materials science communities to have access to raw diffraction data. The effort in archiving raw data for access by the user community is spearheaded by the International Union of Crystallography (IUCr) Committee on Data. In materials science, where powder diffraction is extensively used, the challenge in archiving raw data is different to that from single crystal data, owing to the very nature of the contributions involved. Powder diffraction (X-ray or neutron) data consist of contributions from the material under study as well as instrument specific parameters. Having raw powder diffraction data can be essential in cases of analysing materials with poor crystallinity, disorder, micro structure (size/strain) etc. Here, the initiative and progress made by the International Centre for Diffraction Data (ICDD^R) in archiving powder X-ray diffraction raw data in the Powder Diffraction File^TM (PDF^R) database is outlined. The upcoming 2025 release of the PDF-5+ database will have more than 20 800 raw powder diffraction patterns that are available for reference.</p>","PeriodicalId":7320,"journal":{"name":"Acta crystallographica Section B, Structural science, crystal engineering and materials","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11457107/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142103255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Substitutional/positional disorder of biguanide and guanylurea in the structure of a decavanadate complex [(Bg)(HV₁₀O₂₈^5-)]_0.4[(HGU⁺)(V₁₀O₂₈^6-)]_0.6(H₂Met²⁺)₂(H₃O⁺)·8H₂O.","authors":"Aungkana Chatkon, Kenneth J Haller, Joseph P Haller","doi":"10.1107/S2052520624006929","DOIUrl":"10.1107/S2052520624006929","url":null,"abstract":"<p><p>A hydrated salt of decavanadate containing diprotonated metforminium(2+) (H₂Met²⁺), hydronium (H₃O⁺) and either neutral biguanide (Bg) or monoprotonated guanylurea (HGU⁺) exhibits a previously seen complex charge-stabilized hydrogen-bonded network [Chatkon et al. (2022). Acta Cryst. B78, 798-808]. Charge balance is achieved in two ways through substitutional disorder: a 0.6 occupied HGU⁺ cation is paired with a V₁₀O₂₈^6- anion, and a 0.4 occupied neutral Bg molecule is paired with a HV₁₀O₂₈^5- anion, with the remaining charge in both cases balanced by two H₂Met²⁺ dications and one H₃O⁺ monocation. Bg/HGU⁺ moieties exhibit bifurcated N-H...O hydrogen bonding to the H₃O⁺ cation and are substitutionally/positionally disordered along with the H₃O⁺ cation about an inversion center. The HGU⁺ V₁₀O₂₈^6- synthon seen in the previous study occurs again. Bg exhibits bifurcated hydrogen bonding from two amino groups to two rows of cluster O atoms running diagonally across the equatorial plane of the HV₁₀O₂₈^5- anion with a return hydrogen bond from the cluster H atom to the imino N atom of the Bg. Thus, a Bg...cluster synthon similar to the HGU⁺...cluster synthon previously reported is found. The disordered moieties occupy spaces with excess volume in the 3-D network structure. Interestingly, when the crystallographic unit cell of the current compound, whose X-ray data was collected at 100 K, is compared with that of a previous compound exhibiting the same supramolecular framework, unit-cell parameter c does not shorten as a and b expectantly do because of the lower data collection temperature. The lack of contraction on unit-cell parameter c is possibly due to the supramolecular structure.</p>","PeriodicalId":7320,"journal":{"name":"Acta crystallographica Section B, Structural science, crystal engineering and materials","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142103257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synthesis and properties of Sr₂La₂NiW₂O₁₂, a new S = 1 triangular lattice magnet.","authors":"Anastasiia Smerechuk, Ana Guilherme Buzanich, Bernd Büchner, Sabine Wurmehl, Ryan Morrow","doi":"10.1107/S2052520624007091","DOIUrl":"10.1107/S2052520624007091","url":null,"abstract":"<p><p>Magnetic materials featuring triangular arrangements of spins are frequently investigated as platforms hosting magnetic frustration. Hexagonal perovskites with ordered vacancies serve as excellent candidates for two-dimensional triangular magnetism due to the considerable separation of the magnetic planes. In this work, the effects of chemical pressure on the ferromagnetic ground state of Ba₂La₂NiW₂O₁₂ by substitution of Ba²⁺ with Sr²⁺ to produce Sr₂La₂NiW₂O₁₂ are investigated. The two materials are characterized using synchrotron-based XRD, XANES and EXAFS in addition to magnetometry in order to correlate their crystal structures and magnetic properties. Both materials form in space group R3, yet as a result of the enhanced bending of key bond angles due to the effects of chemical pressure, the T_C value of the magnetic Ni²⁺ sublattice is reduced from ∼6 K in Ba₂La₂NiW₂O₁₂ to 4 K in Sr₂La₂NiW₂O₁₂.</p>","PeriodicalId":7320,"journal":{"name":"Acta crystallographica Section B, Structural science, crystal engineering and materials","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11457098/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142103258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"New insights into the magnetism and magnetic structure of LuCrO₃ perovskite.","authors":"Angel Muñoz, Javier Gainza, Jian Shi Zhou, José Luis Martinez, Eva Céspedes, Maria Teresa Fernández-Díaz, José Antonio Alonso","doi":"10.1107/S2052520624006711","DOIUrl":"10.1107/S2052520624006711","url":null,"abstract":"<p><p>A polycrystalline sample LuCrO₃ has been characterized by neutron powder diffraction (NPD) and magnetization measurements. Its crystal structure has been Rietveld refined from NPD data in space group Pnma; this perovskite contains strongly tilted CrO₆ octahedra with extremely bent Cr-O-Cr superexchange angles of ∼142°. The NPD data show that below Néel temperature (T_N ≃ 131 K), the magnetic structure can be defined as an A-type antiferromagnetic arrangement of Cr³⁺ magnetic moments, aligned along the b axis, with a canting along the c axis. A noticeable magnetostrictive effect is observed in the unit-cell parameters and volume upon cooling down across T_N. The AC magnetic susceptibility indicates the onset of magnetic ordering below 112.6 K; the magnetization isotherms below T_N show a nonlinear behaviour that is associated with the described canting of the Cr³⁺ magnetic moments. From the Curie-Weiss law, the effective moment of the Cr³⁺ sublattice is found to be μ_eff = 3.55 μ_B (calculated 3.7 μ_B) while the Θ_CW parameter yields a value of -155 K, indicating antiferromagnetic interactions. There is a conspicuous increase of T_N upon the application of external pressure, which must be due to shortening of the Cr-O bond length under compression that increases the orbital overlap integral.</p>","PeriodicalId":7320,"journal":{"name":"Acta crystallographica Section B, Structural science, crystal engineering and materials","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11457101/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142131593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A comprehensive characterization of thiophosgene in the solid state.","authors":"Frank Tambornino, Sven Ringelband, Stewart F Parker, Christopher M Howard, Dominic Fortes","doi":"10.1107/S2052520624007583","DOIUrl":"10.1107/S2052520624007583","url":null,"abstract":"<p><p>Thiophosgene is one of the principal C=S building blocks in synthetic chemistry. At room temperature, thiophosgene is a red liquid. While its properties in the liquid and gaseous states are well known, a comprehensive characterization of thiophosgene in its solid state is presented here. Differential scanning calorimetry shows that thiophosgene forms a supercooled melt before rapidly crystallizing. Its melting point is 231.85 K (-41.3 °C). At 80 K, thiophosgene crystallizes in space group P6₃/m [No. 174, a = b = 5.9645 (2), c = 6.2835 (3) Å, V = 193.59 (2) ų]. The molecule shows a distinct rotational disorder: all S and Cl positions are of mixed occupancy and the disorder does not resolve at temperatures as low as 10 K, as was shown by neutron powder diffraction. Infrared, Raman and inelastic neutron scattering spectra were collected and assigned with the aid of quantum chemical calculations. A larger ordered structural model allowed for better agreement between the measured and calculated spectra, further indicating that disorder is an inherent feature of solid-state thiophosgene.</p>","PeriodicalId":7320,"journal":{"name":"Acta crystallographica Section B, Structural science, crystal engineering and materials","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11457100/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142339154","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magnetic space groups versus representation analysis in the investigation of magnetic structures: the happy end of a strained relationship.","authors":"J Rodriguez-Carvajal, J M Perez-Mato","doi":"10.1107/S2052520624007479","DOIUrl":"10.1107/S2052520624007479","url":null,"abstract":"<p><p>In recent decades, sustained theoretical and software developments have clearly established that representation analysis and magnetic symmetry groups are complementary concepts that should be used together in the investigation and description of magnetic structures. Historically, they were considered alternative approaches, but currently, magnetic space groups and magnetic superspace groups can be routinely used together with representation analysis, aided by state-of-the-art software tools. After exploring the historical antagonism between these two approaches, we emphasize the significant advancements made in understanding and formally describing magnetic structures by embracing their combined use.</p>","PeriodicalId":7320,"journal":{"name":"Acta crystallographica Section B, Structural science, crystal engineering and materials","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11457108/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142339159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the magnetic and crystal structures of NiO and MnO.","authors":"V Pomjakushin","doi":"10.1107/S205252062400756X","DOIUrl":"10.1107/S205252062400756X","url":null,"abstract":"<p><p>The magnetic and crystal structures of manganese and nickel monoxides have been studied using high-resolution neutron diffraction. The known 1k-structures based on the single propagation vector [½ ½ ½] for the parent paramagnetic space group Fm3m are forced to have monoclinic magnetic symmetry and are not possible in rhombohedral symmetry. However, the monoclinic distortions from the rhombohedral crystal metric allowed by symmetry are very small, and the explicit monoclinic splittings of the diffraction peaks have not been experimentally observed. We analyse the magnetic crystallographic models metrically compatible with our experimental data in full detail by using isotropy subgroup representation approach, including rhombohedral solutions based on the propagation vector star {[½ ½ ½], [-½ ½ ½], [½-½ ½], [½ ½ -½]}. Although the full star rhombohedral R_I3c structure can equally well fit our diffraction data for NiO, we conclude that the best solution for the crystal and magnetic structures for NiO and MnO is the 1k monoclinic model with the magnetic space group C_c2/c (Belov-Neronova-Smirnova No. 15.90, UNI symbol C2/c.1'_c[C2/m]).</p>","PeriodicalId":7320,"journal":{"name":"Acta crystallographica Section B, Structural science, crystal engineering and materials","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11457103/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142339161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magnetic structure of the noncentrosymmetric magnet Sr₂MnSi₂O₇ through irreducible representation and magnetic space group analyses.","authors":"Y Nambu, M Kawamata, X Pang, H Murakawa, M Avdeev, H Kimura, H Masuda, N Hanasaki, Y Onose","doi":"10.1107/S2052520624007625","DOIUrl":"10.1107/S2052520624007625","url":null,"abstract":"<p><p>Magnetic structures of the noncentrosymmetric magnet Sr₂MnSi₂O₇ were examined through neutron diffraction for powder and single-crystalline samples, as well as magnetometry measurements. All allowed magnetic structures for space group P42₁m with the magnetic wavevector q_m = (0, 0, ½) were refined via irreducible representation and magnetic space group analyses. The compound was refined to have in-plane magnetic moments within the magnetic space group Cmc2₁.1'_c (No. 36.177) under zero field, which can be altered to P2₁2₁2₁.1'_c (No. 19.28) above μ₀H = 0.067 (5) T to align induced weak-ferromagnetic components within one layer on the ab plane. All refined parameters are provided following the recent framework based upon the magnetic space group, which better conveys when exchanging crystallographic information for commensurate magnetic structures.</p>","PeriodicalId":7320,"journal":{"name":"Acta crystallographica Section B, Structural science, crystal engineering and materials","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142339160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}