Acta Crystallographica Section E: Crystallographic Communications最新文献

{"title":"Syntheses and crystal structures of di­chlorido­(2,6-di­methyl­pyrazine-κN)(methanol-κO)zinc(II), di­bromido­(2,6-di­methyl­pyrazine-κN)(methanol-κO)zinc(II) and aqua­(2,6-di­methyl­pyrazine-κN)di­iodido­zinc(II)","authors":"Christian Näther","doi":"10.1107/S2056989026002902","DOIUrl":"10.1107/S2056989026002902","url":null,"abstract":"<div><div>The syntheses and crystal structures of three complexes with the composition ZnCl₂(2,6-di­methyl­pyrazine)(CH₃OH) (<strong>1</strong>), ZnBr₂(2,6-di­methyl­pyrazine)(CH₃OH) (<strong>2</strong>) and ZnI₂(2,6-di­methyl­pyrazine)(H₂O) (<strong>3</strong>) are reported. Each consists of discrete complexes that are linked by hydrogen bonding.</div></div><div><div>Three new compounds with the compositions [ZnCl₂(C₆H₈N₂)(CH₃OH)] (<strong>1</strong>), [ZnBr₂(C₆H₈N₂)(CH₃OH)] (<strong>2</strong>) and [ZnI₂(C₆H₈N₂)(H₂O)] (<strong>3</strong>) were prepared (C₆H₈N₂ = 2,6-di­methyl­pyrazine). The asymmetric unit of each compound consists of one Zn^II cation, two halide anions, one 2,6-di­methyl­pyrazine ligand and one methanol (<strong>1</strong> and <strong>2</strong>) or water mol­ecule (<strong>3</strong>), with all atoms located in general positions. Compounds <strong>1</strong> and <strong>2</strong> are not isostructural. In the crystal structures, the metal cations are fourfold coordinated by two halide anions, one 2,6-di­methyl­pyrazine ligand and one methanol or water mol­ecule within a slightly distorted tetra­hedral geometry. In <strong>1</strong> and <strong>2</strong> the discrete complexes are linked into chains <em>via</em> O—H⋯O hydrogen bonds between the O—H H atom of the methanol mol­ecule and the 2,6-di­methyl­pyrazine N atom that is not involved in the metal coordination. These chains are further linked by weak C—H⋯Cl (<strong>1</strong>) or C—H⋯Br (<strong>2</strong>) inter­actions. In <strong>3</strong>, two complexes are linked by pairwise O—H⋯I hydrogen bonds into centrosymmetric dimeric units that are further connected by strong O—H⋯O hydrogen bonding between the second water H atom and the 2,6-di­methyl­pyrazine N-atom that is adjacent to the two methyl groups.</div></div>","PeriodicalId":7367,"journal":{"name":"Acta Crystallographica Section E: Crystallographic Communications","volume":"82 4","pages":"Pages 388-393"},"PeriodicalIF":0.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147637593","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":"Synthesis and structure of a 1:1 1-phenyl­semicarbazide–1-phenyl­pyrazolidin-3-one cocrystal","authors":"S. Muthu ,&nbsp;V. L. Siji ,&nbsp;S. S. Sreejith ,&nbsp;M. Sithambaresan","doi":"10.1107/S2056989026002550","DOIUrl":"10.1107/S2056989026002550","url":null,"abstract":"<div><div>The title cocrystal was obtained by the cocrystallization of 1-phenyl­semicarbazide (<em>A</em>) and 1-phenyl­pyrazolidin-3-one (<em>B</em>) in a 1:1 molar ratio from methanol solution. The structure features a <em>gauche</em> arrangement about the N—N bond in the semicarbazide fragment and a twisted conformation of the pyrazolidinone ring. In the extended structure, the mol­ecules are linked by <em>A</em> → <em>A</em> and <em>B</em> → <em>A</em> N—H⋯O hydrogen bonds, supplemented by C—H⋯π contacts to generate a three-dimensional supra­molecular framework.</div></div><div><div>The title cocrystal, C₇H₉N₃O·C₉H₁₀N₂O, was obtained by the cocrystallization of 1-phenyl­semicarbazide (<em>A</em>) and 1-phenyl­pyrazolidin-3-one (<em>B</em>) in a 1:1 molar ratio from methanol solution. The structure features a <em>gauche</em> arrangement about the N—N bond in the semicarbazide fragment and a twisted conformation of the pyrazolidinone ring. In the extended structure, the mol­ecules are linked by <em>A</em> → <em>A</em> and <em>B</em> → <em>A</em> N—H⋯O hydrogen bonds, supplemented by C—H⋯π contacts to generate a three-dimensional supra­molecular framework.</div></div>","PeriodicalId":7367,"journal":{"name":"Acta Crystallographica Section E: Crystallographic Communications","volume":"82 4","pages":"Pages 371-374"},"PeriodicalIF":0.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147637633","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":"Crystal structure, spectroscopic characterization, and Hirshfeld surface analysis of (E)-6-(ferrocenylmethyl­idene)-6,7-di­hydro-5H-indeno­[5,6-d][1,3]dioxol-5-one","authors":"José A. Méndez-Román ,&nbsp;Alejandro Burgos-Suazo ,&nbsp;Liz N. Santiago-Martoral ,&nbsp;Dalice M. Piñero Cruz ,&nbsp;Ingrid Montes-González","doi":"10.1107/S2056989026002628","DOIUrl":"10.1107/S2056989026002628","url":null,"abstract":"<div><div>A single crystal of ferrocenyl indanone, which crystallized in the monoclinic space group <em>P</em>2₁/<em>c</em> was investigated by X-ray diffraction, Hirshfeld surface analysis and NMR spectroscopy. In the crystal, mol­ecules are arranged in pairs with asymmetrical stacking by O⋯H inter­molecular inter­actions.</div></div><div><div>The title compound, [Fe(C₅H₅)(C₁₆H₁₁O₃)], was synthesized through a Claisen–Schmidt condensation. The title compound crystallizes in the monoclinic space group <em>P</em>2₁/<em>c</em> with four mol­ecules per unit cell. In the crystal, mol­ecules are arranged in pairs with asymmetrical stacking by O⋯H inter­molecular inter­actions. The ferrocenyl indanone derivative is involved in several inter­molecular inter­actions, including C⋯H, C⋯O, C—H⋯O, and H⋯H contacts. The cyclo­penta­dienyl rings of ferrocene exhibit an average torsion angle of approximately −15.418°. The indanone fragment and the substituted cyclo­penta­dienyl ring are nearly coplanar, forming a dihedral angle of 8.18 (14)°. The Hirshfeld surface analysis qu­anti­fied the contributions from specific inter­actions involving the carbonyl moiety, π–π stacking, and H⋯H contacts. The two-dimensional fingerprint plots and NMR spectra were also analyzed.</div></div>","PeriodicalId":7367,"journal":{"name":"Acta Crystallographica Section E: Crystallographic Communications","volume":"82 4","pages":"Pages 408-412"},"PeriodicalIF":0.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147637578","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":"Crystal structure of (1Z,2Z)-N1,N2-diisobutyl-1,2-di­phenyl­ethane-1,2-di­imine","authors":"Naser E. Eltayeb ,&nbsp;Jamal Lasri ,&nbsp;Yaseen A. Almehmadi ,&nbsp;Tuncer Hökelek ,&nbsp;Aidan P. McKay","doi":"10.1107/S2056989026002227","DOIUrl":"10.1107/S2056989026002227","url":null,"abstract":"<div><div>In the title compound, the dihedral angle between the phenyl rings is 89.23 (5)°. In the crystal, the mol­ecules are elongated along the <em>c</em>-axis direction and stacked along the <em>b</em>-axis direction. Neither intra- or inter­molecular hydrogen bondings nor π–π inter­actiones are observed. The weak C—H⋯π(ring) inter­actions may help in the consolidation of the packing.</div></div><div><div>The asymmetric unit of the title compound, C₂₂H₂₈N₂, contains 1,2-di­phenyl­ethane-1,2-di­imine and diisobutyl groups, with the dihedral angle between the phenyl rings being 89.23 (5)°. In the crystal, the mol­ecules are elongated along the <em>c</em>-axis direction and stacked along the <em>b</em>-axis direction. Neither intra- or inter­molecular hydrogen bondings nor aromatic π–π stacking inter­actions are observed. The weak C—H⋯π(ring) inter­actions may help in the consolidation of the packing.</div></div>","PeriodicalId":7367,"journal":{"name":"Acta Crystallographica Section E: Crystallographic Communications","volume":"82 4","pages":"Pages 345-348"},"PeriodicalIF":0.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147637482","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":"Hydrogen bonds or not? Synthesis and structure of 2,3-di­cyanona­phthalene-1,4-diyl bis­(4-methylbenzene-1-sulfonate)","authors":"Nesuhi Akdemir ,&nbsp;Muhammad Nawaz Tahir ,&nbsp;Muhammad Ashfaq","doi":"10.1107/S2056989026002884","DOIUrl":"10.1107/S2056989026002884","url":null,"abstract":"<div><div>In the title compound, the pendant <em>para</em> toluene moieties are inclined to the central naphthalene-2,3-dicarbo­nitrile grouping by 45.82 (7) and 42.41 (6)°. The crystal packing features offset parallel π–π stacking and C—H⋯π inter­actions.</div></div><div><div>In the title compound, C₂₆H₁₈N₂O₆S₂, the pendant substituted <em>para-</em>toluene moieties are inclined relative to the central naphthalene-2,3-dicarbo­nitrile unit by 45.82 (7) and 42.41 (6)°. In the extended structure, the mol­ecules are linked by offset parallel π–π stacking and C—H⋯π inter­actions to form chains that propagate along the crystallographic <em>b-</em>axis direction. There are no conventional hydrogen bonds according to the usual distance and angle criteria, but a Hirshfeld surface analysis shows various contacts shorter than the van der Waals radii sums of the atoms concerned. The top four contributors to the packing have percentage contributions of 26.8, 26.0, 18.7 and 17.9% for H⋯H, H⋯O, H⋯C and H⋯N, respectively.</div></div>","PeriodicalId":7367,"journal":{"name":"Acta Crystallographica Section E: Crystallographic Communications","volume":"82 4","pages":"Pages 400-403"},"PeriodicalIF":0.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147637598","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":"Syntheses and crystal structures of bis­(2,3-di­methyl­pyrazine-κN)di­iodido­cadmium(II) and catena-poly[[di­iodido­cadmium(II)]-μ-2,3-di­methyl­pyrazine-κ2N1:N4]","authors":"Christian Näther","doi":"10.1107/S2056989026002896","DOIUrl":"10.1107/S2056989026002896","url":null,"abstract":"<div><div>The syntheses and crystal structures of [CdI₂(2,3-di­methyl­pyrazine)₂](<strong>1</strong>) and [CdI₂(2,3-di­methyl­pyrazine)]_<em>n</em> (<strong>2</strong>) are reported. Compound <strong>1</strong> consists of discrete complexes, whereas in <strong>2</strong> the Cd cations are linked into chains by bridging 2,3-di­methyl­pyrazine ligands.</div></div><div><div>The reaction of cadmium iodide with 2,3-di­methyl­pyrazine leads to the formation of two compounds with the compositions [CdI₂(C₆H₈N₂)₂] or [CdI₂(2,3-di­methyl­pyrazine)₂] (<strong>1</strong>) and [CdI₂(C₆H₈N₂)]_<em>n</em> or [CdI₂(2,3-di­methyl­pyrazine)]_<em>n</em> (<strong>2</strong>). The asymmetric unit of <strong>1</strong> is built up of one Cd^II cation as well as two iodide anions and two 2,3-di­methyl­pyrazine ligands representing complete mol­ecules. The Cd^II cations are tetra­hedrally coordinated, forming discrete complexes that are connected <em>via</em> weak C—H⋯I inter­actions. The asymmetric unit of <strong>2</strong> consists of one Cd^II cation and two crystallographically independent iodide anions that are located on a crystallographic mirror plane, as well as one 2,3-di­methyl­pyrazine ligand that is located on a twofold rotation axis. The Cd^II cations are tetra­hedrally coordinated by two iodide anions and two 2,3-di­methyl­pyrazine ligands into corrugated chains. As in <strong>1</strong>, inter­molecular C—H⋯I inter­actions are observed. Comparison of the experimental powder patterns with those calculated from single-crystal data proves that pure compounds have been obtained. The crystal structures are compared with those of related <em>MX</em>₂ (<em>M</em> = Zn, Cd, <em>X</em> = Cl, Br, I) coordination compounds with pyrazine and 2,3-di­methyl­pyrazine, that are reported in the literature.</div></div>","PeriodicalId":7367,"journal":{"name":"Acta Crystallographica Section E: Crystallographic Communications","volume":"82 4","pages":"Pages 394-399"},"PeriodicalIF":0.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147637669","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":"Synthesis, crystal structure and Hirshfeld surface analysis of bis­[N-(4-chloro­benz­yl)-N-do­decyl­dithio­carbamato-κ2S,S′]palladium(II)","authors":"R. Pallavi ,&nbsp;N. Srinivasan ,&nbsp;S. Thirumaran","doi":"10.1107/S205698902600188X","DOIUrl":"10.1107/S205698902600188X","url":null,"abstract":"<div><div>The title compound crystallizes about an inversion centre in the monoclinic space group <em>C</em>2/<em>c</em>. The Pd^II cation adopts a square-planar coordination geometry defined by four sulfur atoms from two <em>N</em>-(4-chloro­benz­yl)-<em>N</em>-do­decyl­dithio­carbamate anions. The crystal packing features C—H⋯S hydrogen bonds, which form a belt motif.</div></div><div><div>The title compound, [Pd(C₂₀H₃₁ClNS₂)₂], crystallizes about an inversion centre in the monoclinic space group <em>C</em>2/<em>c</em>. The Pd^II cation adopts a square-planar coordination geometry defined by four sulfur atoms from two <em>N</em>-(4-chloro­benz­yl)-<em>N</em>-do­decyl­dithio­carbamate anions. The crystal packing features C—H⋯S hydrogen bonds, which form a belt motif. Hirshfeld surface analysis indicates that H⋯H (62.9%), S⋯H/H⋯S (14.0%) and Cl⋯H/H⋯Cl (11.1%) contacts dominate the inter­molecular inter­actions.</div></div>","PeriodicalId":7367,"journal":{"name":"Acta Crystallographica Section E: Crystallographic Communications","volume":"82 4","pages":"Pages 384-387"},"PeriodicalIF":0.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147637692","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":"Crystal structure of (dibenzo-21-crown-7)di­iodido­samarium(II) 1,2-di­meth­oxy­ethane hemisolvate","authors":"Hannah B. Wineinger ,&nbsp;Joseph M. Sperling ,&nbsp;Thomas E. Albrecht","doi":"10.1107/S2056989026001374","DOIUrl":"10.1107/S2056989026001374","url":null,"abstract":"<div><div>The title compound, [SmI₂(C₂₂H₂₈O₇)]·0.5C₄H₁₀O₂ or Sm(dibenzo-21-crown-7)I₂, was obtained as a minor product by layering di­meth­oxy­ethane solutions of SmI₂ and dibenzo-21-crown-7. The asymmetric unit consists of one Sm(dibenzo-21-crown-7)I₂ moiety and half a di­meth­oxy­ethane solvent mol­ecule in the outer sphere.</div></div><div><div>The title compound, [SmI₂(C₂₂H₂₈O₇)]·0.5C₄H₁₀O₂ or Sm(dibenzo-21-crown-7)I₂·0.5dimethoxyethane, was obtained as a minor product by layering di­meth­oxy­ethane solutions of SmI₂ and dibenzo-21-crown-7. The asymmetric unit consists of one Sm(dibenzo-21-crown-7)I₂ moiety and half a di­meth­oxy­ethane solvent mol­ecule in the outer sphere. Of the seven oxygen atoms available for coordination in dibenzo-21-crown-7, only six are coordinated, forming a plane of coordination around samarium(II). The remaining oxygen and its adjacent benzene ring ‘jack knife’ perpendicularly relative to this plane of coordination.</div></div>","PeriodicalId":7367,"journal":{"name":"Acta Crystallographica Section E: Crystallographic Communications","volume":"82 4","pages":"Pages 362-365"},"PeriodicalIF":0.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147637520","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":"Crystal structures of the homologues diethyl and dimethyl (10H-indeno­[1,2-b]quinoxalin-11-yl)phospho­nate: use of non-spherical scattering factors","authors":"Ghada A. Eldeken ,&nbsp;Fatma A. El-Samahy ,&nbsp;Ehab M. Zayed ,&nbsp;Fayez H. Osman ,&nbsp;Khaled Mahmoud ,&nbsp;Galal H. Elgemeie ,&nbsp;Peter G. Jones","doi":"10.1107/S2056989026001842","DOIUrl":"10.1107/S2056989026001842","url":null,"abstract":"<div><div>The tetra­cyclic ring systems of the two title structures are essentially planar. Mol­ecules are linked by hydrogen bonds N—H⋯O=P, forming rings of graph set <em>R</em>²₂(12).</div></div><div><div>The two title compounds, <strong>4a</strong> C₁₉H₁₉N₂O₃P and <strong>4b</strong> C₁₇H₁₅N₂O₃P, are not isotypic. The tetra­cyclic ring systems are essentially planar. The phospho­nate groups are similarly oriented. Compound <strong>4a</strong> crystallizes in <em>P</em>1 with <em>Z</em>′ = 1; mol­ecules are linked in inversion-symmetric pairs by classical hydrogen bonds N—H⋯O=P, forming rings of graph set <em>R</em>²₂(12). Compound <strong>4b</strong> crystallizes in <em>P</em>2₁/<em>c</em> with <em>Z</em>′ = 2; the two independent mol­ecules are linked by a hydrogen-bond system analogous to that of <strong>4a</strong>, but the ring systems subtend an inter­planar angle of 55.84 (1)°. For <strong>4a</strong>, the hydrogen bonding combines with ring stacking in pairs to form a ribbon structure parallel to the <em>b</em> axis. For <strong>4b</strong>, the classical hydrogen bonding combines with two ‘weak’ hydrogen bonds C—H⋯O to form a layer structure parallel to the <em>ac</em> plane. Non-spherical atom scattering factors were employed (using the program <em>NoSpherA2</em>) to avoid the problem of badly fitting reflections in high-resolution data (2θ_max<em>ca</em> 105° using Mo <em>K</em>α radiation).</div></div>","PeriodicalId":7367,"journal":{"name":"Acta Crystallographica Section E: Crystallographic Communications","volume":"82 4","pages":"Pages 320-325"},"PeriodicalIF":0.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147637606","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":"Crystal structure of Na4(As2O5)(H2O)0.5 and a survey of the pyroarsenite anion, (As2O5)4−","authors":"Tobias Wolflehner ,&nbsp;Matthias Weil","doi":"10.1107/S2056989026002859","DOIUrl":"10.1107/S2056989026002859","url":null,"abstract":"<div><div>The crystal structure of Na₄(As₂O₅)(H₂O)_0.5 consists of a half-eclipsed (As₂O₅)^4– anion embedded in a framework of [NaO₄] and [NaO₆] polyhedra. O—H⋯O hydrogen-bonding consolidates the packing.</div></div><div><div>The title compound, tetra­sodium pyroarsenite hemihydrate, [Na₄(As₂O₅)(H₂O)_0.5], represents the first pyroarsenite compound of an alkali metal. The asymmetric unit comprises four Na, two As, five O sites and one H site in a general position, and one water O atom located on a twofold rotation axis in space group <em>C</em>2/<em>c</em>. The (As₂O₅)^4– anion is made up from two trigonal-pyramidal {AsO₃} units sharing a corner. In the crystal structure, all O atoms of the anion are also part of a framework defined by one [NaO₄] and three [NaO₆] coordination polyhedra. Almost linear hydrogen-bonding inter­actions of medium strength [O⋯O 2.651 (4) Å; O—H⋯O 171 (6)°] between the water mol­ecule and one of the terminal O atoms of the pyroarsenite anion consolidate the crystal structure. Data mining for structural data on isolated pyroarsenite anions resulted in 30 (As₂O₅)^4– groups present in various crystal structures. In these pyroarsenite anions, the mean As—O distance to terminal oxygen atoms is 1.764 (33) Å and to bridging oxygen atoms 1.856 (64) Å. The values of the As—O—As bridging angle are highly variable [range 107.78 (13) to 144.12 (5)°], with that of Na₄(As₂O₅)(H₂O)_0.5 having by far the smallest value of all structures chacterized so far.</div></div>","PeriodicalId":7367,"journal":{"name":"Acta Crystallographica Section E: Crystallographic Communications","volume":"82 4","pages":"Pages 379-383"},"PeriodicalIF":0.6,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147637531","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}