Showing papers in "Acta Crystallographica Section E-structure Reports Online in 2005"
TL;DR: The structure of cerium diruthenium decaaluminium, CeRu2Al10, is characterized by seven crystallographic sites in space group Cmcm, viz. Ce in 4c, Ru in 8a, two Al atoms in 8g, two AL atoms in eightf and one Al atom in 8e as discussed by the authors.
Abstract: The structure of cerium diruthenium decaaluminium, CeRu2Al10, is characterized by seven crystallographic sites in space group Cmcm, viz. Ce in 4c, Ru in 8a, two Al atoms in 8g, two Al atoms in 8f and one Al atom in 8e. The structure can be interpreted as a stacking of alternating columns running along [001], each formed by only one type of Ru cuboid with composition RuAl6 or CeRuAl4.
53 citations
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TL;DR: The crystal structure of the ortho-rhombic phase I of l-cysteine, C3H7NO2S, has been determined at 30'K as mentioned in this paper.
Abstract: The crystal structure of the orthorhombic phase I of l-cysteine, C3H7NO2S, has been determined at 30 K. The molecule adopts a gauche+ conformation and the structure consists of zwitterions connected into sinusoidal layers by N—H⋯O hydrogen bonds. Further N—H⋯O hydrogen bonds connect the structure into a three-dimensional array. Under ambient conditions, the thiol H atom is disordered in such a way as to form intermolecular S—H⋯S and S—H⋯O hydrogen bonds. At 30 K the structure is ordered with retention of the S—H⋯S contacts [S⋯S = 3.8489 (4) A, S—H⋯S = 2.66 (3) A and S—H⋯S = 150.8 (16)°].
50 citations
TL;DR: Single crystals of p-aminobenzoic acid, C7H7NO2, were grown from water and hydrogen bonds between adjacent molecules lead to the formation of a three-dimensional network.
Abstract: Single crystals of p-aminobenzoic acid, C7H7NO2, were grown from water. In the structure, there is one molecule of the acid present in the asymmetric unit. Hydrogen bonds between adjacent molecules lead to the formation of a three-dimensional network.
38 citations
TL;DR: The title compound [U(C5H6O4)O2] consists of (UO2)2O8 dimers connected by n-pentane-1,5-di-carboxylate (glutaric acid) molcules to form chains running in the [010] direction.
Abstract: The title compound, [U(C5H6O4)O2], consists of (UO2)2O8 dimers connected by n-pentane-1,5-dicarboxylate (glutaric acid) molecules to form chains running in the [010] direction. These chains are further connected by the carboxylate ligand to form sheets in the (10\overline 2) plane.
36 citations
TL;DR: The structure of fampridine (EL-970) or 4-amino-pyridine, C5H6N2, has been redetermined at 150'K as mentioned in this paper.
Abstract: The structure of fampridine (EL-970) or 4-aminopyridine, C5H6N2, has been redetermined at 150 K. The room-temperature structure has been reported previously [Chao & Schempp (1977). Acta Cryst. B33, 1557–1564]. Pyramidalization at the amine N atom occurs in fampridine, with the N atom 0.133 (11) A from the plane of the three C/H/H atoms to which it is bonded; the interplanar angle between the pyridyl ring and NH2 group is 21 (2)°. Aggregation in the solid state occurs by N—H⋯N and N—H⋯π(pyridine) interactions with N⋯N and N⋯π(centroid) distances of 2.9829 (18) and 3.3954 (15) A, respectively; a C—H⋯π(pyridine) contact completes the intermolecular interactions [C⋯π(centroid) = 3.6360 (16) A].
30 citations
TL;DR: In the title compound, C23H16N2O3·CH4O, the N-N bond distance in the pyrazole ring, which is planar within 0.008
Abstract: In the title compound, C23H16N2O3·CH4O, the N—N bond distance in the pyrazole ring, which is planar within 0.008 A, is 1.3634 (18) A. The crystal packing is stabilized by O—H⋯O, O—H⋯N and C—H⋯O intermolecular hydrogen bonds.
27 citations
TL;DR: In this article, single crystals of LaAlO3 (lanthanum aluminium trioxide) have been synthesized at 4.5 GPa and 1273 K in the presence of an NaCl + KCl flux.
Abstract: Single crystals of LaAlO3 (lanthanum aluminium trioxide) have been synthesized at 4.5 GPa and 1273 K, in the presence of an NaCl + KCl flux. The compound crystallizes with the cubic perovskite structure (space group Pm\overline{3}m). The thermal vibration of the O atom is remarkably suppressed in the directions of the Al—O bonds, and this anisotropy ranks among the largest observed in stoichiometric cubic perovskites.
25 citations
TL;DR: In this article, the authors describe the structure of C13H9NO2, a planar compound with strong inter-molecular π−π inter-actions in the crystal structure.
Abstract: The molecule of the title compound, C13H9NO2, is planar, and is disordered so that there are two conformations (1:1) of the phenol ring with respect to the benzoxazole group. Strong intermolecular π–π interactions are noted in the crystal structure.
24 citations
TL;DR: In this paper, the structure of α-4-(β-d-galactopyran-osido)-d-glucopyrans-ose, more commonly known as α-lactose monohydrate, C12H22O11·H2O, has been previously studied by single-crystal diffraction at ca 296 K.
Abstract: The structure of the monohydrate of α-4-(β-d-galactopyranosido)-d-glucopyranose, more commonly known as α-lactose monohydrate, C12H22O11·H2O, has been previously studied by single-crystal diffraction at ca 296 K [Beevers & Hansen (1971). Acta Cryst. B27, 1323–1325; Fries et al. (1971). Acta Cryst. B27, 994–1005; Noordik et al. (1984). Z. Kristallogr. 168, 59–65]. This redetermination at low temperature [150 (2) K] shows improved precision of geometry. Graph-set analysis of the hydrogen-bonding motifs is presented for the first time.
23 citations
TL;DR: The crystal structure of piperazinediium hexa-aqua-zinc(II) bis-sulfate, (C4H12N2)[Zn(H2O)6]2+, SO42− and C4H 12N22+ ions linked together by a hydrogen-bonding network is described in this paper.
Abstract: The crystal structure of piperazinediium hexaaquazinc(II) bis(sulfate), (C4H12N2)[Zn(H2O)6](SO4)2, is built from isolated [Zn(H2O)6]2+, SO42− and C4H12N22+ ions linked together by a hydrogen-bonding network. The title compound exhibits strong analogies with some double aluminium sulfates, also known as Tutton's salts.
22 citations
TL;DR: In this article, the title compound, C7H5NO3S, is linked by paired N−H⋯O=C hydrogen bonds into R22(8) dimers and these dimers are linked into a three-dimensional framework structure by a combination of three independent C−H−O hydrogen bonds.
Abstract: Molecules of the title compound, C7H5NO3S, are linked by paired N—H⋯O=C hydrogen bonds into R22(8) dimers and these dimers are linked into a three-dimensional framework structure by a combination of three independent C—H⋯O hydrogen bonds.
TL;DR: The crystal structure of hydrochloro-thia-zide form II, C7H8ClN3O4S2, was solved by simulated annealing from laboratory X-ray powder diffraction data collected at room temperature to 1.76 A resolution as discussed by the authors.
Abstract: The crystal structure of hydrochlorothiazide form II, C7H8ClN3O4S2, was solved by simulated annealing from laboratory X-ray powder diffraction data collected at room temperature to 1.76 A resolution. Subsequent Rietveld refinement yielded an Rwp of 0.0376 to 1.49 A resolution. The molecules crystallize in the space group P21/c with one molecule in the asymmetric unit. The structure is stabilized by three N—H⋯N and one N—H⋯O hydrogen-bonded intermolecular interaction.
TL;DR: The single-crystal neutron diffraction technique was used to determine the crystal structure of melamine, C3H6H6, at 14'K as discussed by the authors, which is nearly planar and has three crystallographically inequivalent amine groups with different geometries.
Abstract: The single-crystal neutron diffraction technique was used to determine the crystal structure of melamine, C3H6H6, at 14 K The molecule is nearly planar There are three crystallographically inequivalent amine groups with different geometries, the asymmetric unit being the complete molecule
TL;DR: In this article, the terminal meth-yl C atom with respect to the β-C atom is transformed and the crystal structure is stabilized by a network of characteristic head-to-tail dl1 and dl2 sequences.
Abstract: In the title compound, C5H11NO2S, the conformation of the terminal methyl C atom with respect to the β-C atom is trans. The crystal structure is stabilized by a network of characteristic head-to-tail dl1 and dl2 sequences.
TL;DR: A new polymorph of 1H-benzotriazole, C6H5N3, with a melting point of 372 K and a crystal density of 1.33 Mg m−3, has been obtained by recrystallization from acetone.
Abstract: A new polymorph of 1H-benzotriazole, C6H5N3, with a melting point of 372 K and a crystal density of 1.33 Mg m−3, has been obtained by recrystallization from acetone. The triclinic unit cell contains ten molecules joined by N—H⋯N hydrogen bonds into a discrete large supramolecular macrocycle.
TL;DR: Sildenafil citrate is well known as Viagra for the treatment of erectile dysfuncion as discussed by the authors, and it has been shown to be stable by several hydrogen bonds.
Abstract: Sildenafil citrate is well known as Viagra for the treatment of erectile dysfuncion. In the title compound (systematic name: 1-{[3-(6,7-Dihydro-1-methyl-7-oxo-3-propyl-1H-pyrazolo[4,3-d]pyrimidin-5-yl)-4-ethoxyphenyl]sulfonyl}-4-methylpiperazinium citrate monohydrate), C22H31N6O4S+·C6H7O7−·H2O, the pyrazolopyrimidone ring system and the benzene ring are almost coplanar, enabling an intramolecular hydrogen bond between the pyrazolopyrimidone NH group and the O atom of the ethoxy group. One of the N atoms of the piperazine ring is protonated and the citrate molecule exists as an anion. The crystal packing is stabilized by several hydrogen bonds.
TL;DR: The structure of topaz-OD, dialuminium orthosilicate dihydro-xide, Al2SiO4(OD)2, was refined in the space group Pbnm by Rietveld analysis of constant wavelength neutron powder diffraction data as mentioned in this paper.
Abstract: The structure of topaz-OD, dialuminium orthosilicate dihydroxide, Al2SiO4(OD)2, was refined in the space group Pbnm by Rietveld analysis of constant wavelength neutron powder diffraction data. Two non-equivalent half-occupied deuterium positions were located. Each D atom is characterized by an irregular trifurcated hydrogen-bond geometry. The refined hydrogen-bond distances are in the ranges 2.038 (5)–2.281 (6) and 2.280 (5)–2.524 (6) A for the two D atoms. Hydrogen-bond angles range from 83.6 (4) to 151.9 (4)°. Results indicate that it is feasible to characterize the hydrogen bonding in small-volume samples (25 mg) synthesized at high pressure and temperature.
TL;DR: In this paper, an improved structure model with previously unknown site preferences determined was presented, showing that Ti prefers the slightly more regular 4c octahedral site, leaving more room for Al at the 8f octagonal site.
Abstract: beta-Al2TiO5 (dialuminium titanium pentaoxide), grown by rapid cooling of a melt of equimolar amounts of Al2O3 and TiO2, adopts the same overall structure as that crystallized by more conventional methods, such as sintering. Nevertheless, reinvestigation of this structure has resulted in an improved structure model with previously unknown site preferences determined. Ti prefers the slightly more regular 4c octahedral site, leaving more room for Al at the 8f octahedral site. The formula has been determined as ([4c])[Al-0.626 ((7)) Ti-0.374 ((7))]([8f])- [Al-0.687 ((3)) Ti-0.313 ((3))](2)O-5.
TL;DR: The title compound, poly[N,N, N, N′,N′ and N′-tetra-methyl-propane-1,3-diaminium [aqua-to-oxotri-μ3-sulfatodiuranate(VI)]n, contains two-dimensional [(UO2)2(SO4)3(H2O)]2− layers that are unprecedented in uranium chemistry as mentioned in this paper.
Abstract: The title compound, poly[N,N,N′,N′-tetramethylpropane-1,3-diaminium [aquatetraoxotri-μ3-sulfatodiuranate(VI)]], (C7H20N2)[(UO2)2(SO4)3(H2O)]n, contains two-dimensional [(UO2)2(SO4)3(H2O)]2− layers that are unprecedented in uranium chemistry The layers in this compound are separated by C7H20N22+ cations, forming the basis of an extensive hydrogen-bonding network An independent intralayer hydrogen-bonding network is also observed, involving water molecules bound directly to a uranium centre
TL;DR: The title compound, 2-{(E)-3]-(E)4-chloro-phenylimino]-4-hydroxyphenyl-diazenyl}benzoic acid hemihydrate, C20H14ClN3O3·0.5H2O, forms sheets, parallel to the (100) plane, that are linked by weak aromatic C-H⋯O interactions as mentioned in this paper.
Abstract: The title compound, 2-{(E)-3-[(E)-4-chlorophenylimino]-4-hydroxyphenyldiazenyl}benzoic acid hemihydrate, C20H14ClN3O3·0.5H2O, forms sheets, parallel to the (100) plane, that are linked by weak aromatic C—H⋯O interactions. These sheets are in turn linked by strong hydrogen bonds to interstitial water molecules.
TL;DR: In the crystal structure of the title compound, Zn(C12H10N2O6)(H2O)3]·2H 2O}n, the ZnII atom is located on a twofold axis and is coordinated by two carboxylate O atoms and three water O atoms in a trigonal-bipyramidal geometry.
Abstract: In the crystal structure of the title compound, {[Zn(C12H10N2O6)(H2O)3]·2H2O}n, the ZnII atom is located on a twofold axis and is coordinated by two carboxylate O atoms and three water O atoms in a trigonal-bipyramidal geometry. The diacetate ligands connect ZnII atoms to generate one-dimensional zigzag chains, which are linked together by intermolecular hydrogen bonding to form a three-dimensional supramolecular framework.
TL;DR: The crystal structure of the title compound, [Pd(C5H7O2)2], has been redetermined at 100k using modern equipment, resulting in improved precision compared to the previous study as mentioned in this paper.
Abstract: The crystal structure of the title compound, [Pd(C5H7O2)2], has been redetermined at 100 K using modern equipment, resulting in improved precision compared to the previous study [Knyazeva et al. (1970). Zh. Strukt. Khim. 11, 938–939]. The new measurements reveal that the plane of the 2,4-pentanedionate ligand is tilted by 3.4 (1)° with respect to the PdO4 unit (Pd site symmetry = \overline{1}). Possible reasons for this bending are examined in terms of previously undiscussed intermolecular interactions.
TL;DR: The structure of the title compound, (C5H7N5)2[SnCl6]Cl2·4H2O, can be described as alternating layers of [SnCl 6]2− ions along the b axis, the SnIV atom lying on a twofold axis.
Abstract: The structure of the title compound, (C5H7N5)2[SnCl6]Cl2·4H2O, can be described as alternating layers of C5H7N52+ and [SnCl6]2− ions along the b axis, the SnIV atom lying on a twofold axis. The chloride ions are located between the organic entities, forming hydrogen bonds with the N atoms and water molecules. Layers of adeninium cations and hexachlorostannate anions are linked by anion–cation, cation–water and water–water hydrogen bonds. This three-dimensional complex network of hydrogen bonds ensures the cohesion of the ionic structure.
TL;DR: In this article, a dinuclear iron(III) complex with a distorted square-pyramidal coordination geometry is described, where the Fe atom is coordinated by two N atoms and two O atoms of the Schiff base ligand, and the apical position is occupied by a bridging O2− ion.
Abstract: The title compound, μ-oxo-bis({2,2-[propane-1,2-diylbis(nitrilomethylidyne)]diphenolato}iron(III)), [Fe2(C17H16N2O2)2O], is an unusual dinuclear iron(III) complex. Each FeIII ion has a distorted square-pyramidal coordination geometry. In the basal plane, the Fe atom is coordinated by two N atoms and two O atoms of the Schiff base ligand. The apical position is occupied by a bridging O2− ion, which links to the other FeIII ion in the complex. In the crystal structure, pairs of dinuclear iron(III) units form dimers by way of a pair of intermolecular C—H⋯O interactions. The dimers stack along the a axis and there are no other short intermolecular contacts.
TL;DR: The structure of trisodium phosphide, Na3P, known from X-ray powder diffraction data, has been refined based on single-crystal data as discussed by the authors.
Abstract: The structure of trisodium phosphide, Na3P, known from X-ray powder diffraction data, has been refined based on single-crystal data. The compound crystallizes in the hexagonal A3B (A = alkali metal and B = group 15 element) structure type and is isotypic with the homologous potassium phase. The framework is built of Na+ and P3− ions arranged in two kinds of layers perpendicular to the c axis. Two of the Na atoms and the P atom reside at positions of \overline{6}m2 (2b), 3m (4f) and \overline{6}m2 (2c) site symmetry, respectively.
TL;DR: In the title compound, C4H9N2O3+·C6H2N3O7−, the two ions are connected by strong asymmetric O-H⋯O hydrogen bonds as discussed by the authors.
Abstract: In the title compound, C4H9N2O3+·C6H2N3O7−, the two ions are connected by strong asymmetric O—H⋯O hydrogen bonds. The cation is involved in a Z1 (zigzag) head-to-tail sequence along the b axis. The torsion angle χ21 corresponds to a cis conformation. Hydrophobic layers across z = {1\over 2} are sandwiched between hydrophilic layers across the z = 0 plane.
TL;DR: In this article, the asymmetric unit consits of one zinc cation which is located on a centre of symmetry, half of an acetyl-enedicarboxyl-ate anion, the anion lying on a twofold axis, and one water mol-ecule in a general position.
Abstract: From a solution of [Zn(H2O)6](NO3)2 and acetylenedicarboxylic acid in deionized water, single crystals of zinc acetylenedicarboxylate dihydrate, {[Zn(C4O4)(H2O)2]}n, were obtained by slow evaporation of the solvent. The asymmetric unit consits of one zinc cation which is located on a centre of symmetry, half of an acetylenedicarboxylate anion, the anion lying on a twofold axis, and one water molecule in a general position. Thus, zinc is octahedrally coordinated by four O atoms of acetylenedicarboxylate anions and two water molecules in trans positions. These octahedra are connected by dicarboxylate ligands into a three-dimensional network.
TL;DR: In the case of C12H8ClN3O2, the dihedral angle between the least-squares planes of the pyridine and benzene rings is 20.8°(1)° as discussed by the authors.
Abstract: In the title compound, C12H8ClN3O2, the dihedral angle between the least-squares planes of the pyridine and benzene rings is 20.8 (1)°. In the crystal structure, molecules pack nearly parallel along the a axis, with some π stacking interactions.