Crystal structures of isotypic poly[bis(benzimidazolium) [tetra-μ-iodido-stannate(II)]] and poly[bis(5,6-difluorobenzimidazolium) [tetra-μ-iodido-stannate(II)]]

The isostructural title compounds, {(C7H7N2)2[SnI4]}n, (1), and {(C7H5F2N2)2[SnI4]}n, (2), show a layered perovskite-type structure composed of anionic {[SnI4]2−}nsheets parallel to (100), which are decorated on both sides with templating benzimidazolium or 5,6-difluorobenzimidazolium cations, respectively. These planar organic heterocycles mainly form N—H...I hydrogen bonds to the terminal I atoms of the corner-sharing [SnI6] octahedra (point group symmetry 2) from the inorganic layer, but not to the bridging ones. This is in contrast to most of the reported structures of related compounds where ammonium cations are involved. Here hydrogen bonding to both types of iodine atoms and thereby a distortion of the inorganic layers to various extents is observed. For (1) and (2), all Sn—I—Sn angles are linear and no out-of-plane distortions of the inorganic layers occur, a fact of relevance in view of the material properties. The arrangement of the aromatic cations is mainly determined through the direction of the N—H...I hydrogen bonds. The coherence between organic bilayers along [100] is mainly achieved through van der Waals interactions.

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Crystal structure of SrGeO3in the high-pressure perovskite-type phase

Acta Crystallographica Section E Crystallographic Communications ◽

10.1107/s2056989015007264 ◽

2015 ◽

Vol 71 (5) ◽

pp. 502-504 ◽

Cited By ~ 8

Author(s):

Akihiko Nakatsuka ◽

Hiroshi Arima ◽

Osamu Ohtaka ◽

Keiko Fujiwara ◽

Akira Yoshiasa

Keyword(s):

Crystal Structure ◽

High Pressure ◽

Point Group ◽

Group Symmetry ◽

Point Group Symmetry ◽

Thermal Vibrations ◽

Perovskite Type ◽

Pressure Phase ◽

Perovskite Type Structure ◽

The Ideal

Single crystals of the SrGeO3(strontium germanium trioxide) high-pressure phase have been synthesized successfully at 6 GPa and 1223 K. The compound crystallizes with the ideal cubic perovskite-type structure (space groupPm-3m), which consists of a network of corner-linked regular GeO6octahedra (point-group symmetrym-3m), with the larger Sr atoms located at the centers of cavities in the form of SrO12cuboctahedra (point-group symmetrym-3m) in the network. The degrees of covalencies included in the Sr—O and the Ge—O bonds calculated from bond valences are 20.4 and 48.9%, respectively. Thus, the Ge—O bond of the GeO6octahedron in the SrGeO3perovskite has a strong covalency, comparable to those of the Si—O bonds of the SiO4tetrahedra in silicates with about 50% covalency. The thermal vibrations of the O atoms in the title compound are remarkably suppressed in the directions of the Ge—O bonds. This anisotropy ranks among the largest observed in stoichiometric cubic perovskites.

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Crystal structure of post-perovskite-type CaIrO3reinvestigated: new insights into atomic thermal vibration behaviors

Acta Crystallographica Section E Crystallographic Communications ◽

10.1107/s2056989015015649 ◽

2015 ◽

Vol 71 (9) ◽

pp. 1109-1113

Author(s):

Akihiko Nakatsuka ◽

Kazumasa Sugiyama ◽

Akira Yoneda ◽

Keiko Fujiwara ◽

Akira Yoshiasa

Keyword(s):

Crystal Structure ◽

Atmospheric Pressure ◽

Structure Refinement ◽

Point Group ◽

Group Symmetry ◽

Point Group Symmetry ◽

X Ray ◽

Thermal Vibrations ◽

Perovskite Type ◽

Shared Edge

Single crystals of the title compound, the post-perovskite-type CaIrO3[calcium iridium(IV) trioxide], have been grown from a CaCl2flux at atmospheric pressure. The crystal structure consists of an alternate stacking of IrO6octahedral layers and CaO8hendecahedral layers along [010]. Chains formed by edge-sharing of IrO6octahedra (point-group symmetry 2/m..) run along [100] and are interconnected along [001] by sharing apical O atoms to build up the IrO6octahedral layers. Chains formed by face-sharing of CaO8hendecahedra (point-group symmetrym2m) run along [100] and are interconnected along [001] by edge-sharing to build up the CaO8hendecahedral layers. The IrO6octahedral layers and CaO8hendecahedral layers are interconnected by sharing edges. The present structure refinement using a high-power X-ray source confirms the atomic positions determined by Hiraiet al.(2009) [Z. Kristallogr.224, 345–350], who had revised our previous report [Sugaharaet al.(2008).Am. Mineral.93, 1148–1152]. However, the displacement ellipsoids of the Ir and Ca atoms based on the present refinement can be approximated as uniaxial ellipsoids elongating along [100], unlike those reported by Hiraiet al.(2009). This suggests that the thermal vibrations of the Ir and Ca atoms are mutually suppressed towards the Ir...Ca direction across the shared edge because of the dominant repulsion between the two atoms.

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Ion-Exchangeable Oxides with Layered Perovskite Structures as Photocatalysts for Overall Water Splitting

MRS Proceedings ◽

10.1557/proc-454-177 ◽

1996 ◽

Vol 454 ◽

Cited By ~ 2

Author(s):

T. Takata ◽

K. Shinohara ◽

A. Tanaka ◽

M. Hara ◽

J. N. Kondo ◽

...

Keyword(s):

Reaction Mechanism ◽

Water Splitting ◽

Alkaline Solution ◽

Layered Perovskite ◽

Stoichiometric Ratio ◽

Aqueous Alkaline Solution ◽

Overall Water Splitting ◽

The One ◽

Perovskite Type ◽

Perovskite Type Structure

ABSTRACTA novel series of photocatalysts for an overall water splitting is reported. The catalysts have a layered perovskite type structure with a general formula of A2−xLa2Ti3−xNbxO10 (A = K, Rb, Cs; x = 0, 0.5, 1.0). The catalysts, except for the one with x=1.0, are spontaneously hydrated, and the band gap irradiation induced efficient evolution of H2 and O2 in a stoichiometric ratio from an aqueous alkaline solution when a proper amount of Ni loading was made. The reaction mechanism of water splitting on these catalysts is discussed on the bases of the structural study of the catalysts.

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A [Cu3(μ3-O)]–pyrazolate metallacycle with terminal nitrate ligands exhibiting point group symmetry 3

Acta Crystallographica Section E Crystallographic Communications ◽

10.1107/s2056989016003741 ◽

2016 ◽

Vol 72 (4) ◽

pp. 492-494 ◽

Cited By ~ 3

Author(s):

Logesh Mathivathanan ◽

Raquel Cruz ◽

Raphael G. Raptis

Keyword(s):

Hydrogen Bonds ◽

Coordination Sphere ◽

Title Compound ◽

Complex Anion ◽

Rotation Axis ◽

Point Group ◽

Group Symmetry ◽

Nitrate Anion ◽

Point Group Symmetry ◽

Π Interactions

The trinuclear triangular cuprate anion of the title compound, tris[bis(triphenylphosphoranylidene)ammonium] tris(μ2-4-chloropyrazolato-κ2N:N′)-μ3-oxido-tris[(nitrato-κ2O,O′)cuprate(II)] nitrate monohydrate, (C36H30P2N)[Cu3(C3H2ClN2)3(NO3)3O]NO3·H2O, has point group symmetry 3., with the μ3-O atom located on the threefold rotation axis. The distorted square-pyramidal coordination sphere of the CuIIatom is completed by two N atoms oftrans-bridging pyrazolate groups and a chelating nitrate anion. The complex anion is slightly bent, with the nitrate and pyrazolate groups occupying positions above and below the Cu3plane, respectively. In the crystal, weak O—H...O and C—H...O hydrogen bonds, as well as π–π interactions, are present.

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Crystal structure of [Co(NH3)6][Co(CO)4]2

Acta Crystallographica Section E Crystallographic Communications ◽

10.1107/s2056989015020290 ◽

2015 ◽

Vol 71 (11) ◽

pp. 1418-1420 ◽

Cited By ~ 1

Author(s):

Thomas G. Müller ◽

Florian Kraus

Keyword(s):

Crystal Structure ◽

High Pressure ◽

Hydrogen Bonds ◽

Liquid Ammonia ◽

Point Group ◽

Group Symmetry ◽

Point Group Symmetry ◽

Distorted Tetrahedron ◽

Carbonyl Ligands ◽

Set Up

Hexaamminecobalt(II) bis[tetracarbonylcobaltate(-I)], [Co(NH3)6][Co(CO)4]2, was synthesized by reaction of liquid ammonia with Co2(CO)8. The CoIIatom is coordinated by six ammine ligands. The resulting polyhedron, the hexaamminecobalt(II) cation, exhibits point group symmetry -3. The Co-Iatom is coordinated by four carbonyl ligands, leading to a tetracarbonylcobaltate(−I) anion in the shape of a slightly distorted tetrahedron, with point group symmetry 3. The crystal structure is related to that of high-pressure BaC2(space groupR-3m), with the [Co(NH3)6]2+cations replacing the Ba sites and the [Co(CO)4]−anions replacing the C sites. N—H...O hydrogen bonds between cations and anions stabilize the structural set-up in the title compound.

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1H, 2H and 13C NMR Studies of Cation Dynamics in a Layered Perovskite-Type Incommensurate Compound (n-C3H7NH3)2CdCl4

Zeitschrift für Naturforschung A ◽

10.1515/zna-2002-6-729 ◽

2002 ◽

Vol 57 (6-7) ◽

pp. 451-455 ◽

Cited By ~ 1

Author(s):

Koh-ichi Suzuki ◽

Hiroki Fujimori ◽

Tetsuo Asaji ◽

Shin’ichi Ishimaru ◽

Ryuichi Ikeda

Keyword(s):

Hydrogen Bonds ◽

13C Nmr ◽

Molecular Axis ◽

Layered Perovskite ◽

Inorganic Layer ◽

Nmr Studies ◽

Increasing Temperature ◽

Perovskite Type ◽

C Nmr

Cation dynamics in (n-C3H7NH3)2CdCl4 and (n-C3H7ND3)2CdCl4 were investigated by 1H, 2H, and 13C NMR measurements. An overall motion of the cation being associated with the fluctuation of the molecular axis is suggested to be activated with increasing temperature. The cationic motion is enhanced at the counter side of the -NH3+ group probably because the group is bound with the inorganic layer through the N-H...Cl hydrogen bonds

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Charge Distribution Model in Cubic Perovskite-type Compounds

Zeitschrift für Naturforschung A ◽

10.1515/zna-2000-1-246 ◽

2000 ◽

Vol 55 (1-2) ◽

pp. 261-266

Author(s):

R. E. Alonso ◽

A. López-García

Keyword(s):

Oxygen Vacancies ◽

Computational Simulation ◽

Point Group ◽

Group Symmetry ◽

Distribution Model ◽

Cubic Symmetry ◽

Cell Parameters ◽

Common Trend ◽

Charge Model ◽

Perovskite Type

A non-zero electric field gradient tensor, detected by probes that occupy sites with cubic point group symmetry, was observed in many AB03 perovskite-type compounds. This breakdown of local cubic symmetry is commonly associated with the presence of oxygen vacancies around the probe. This effect in BaTixHf1-xO3, with x = 0.7, 0.5, 0.3, 0.1, 0.05 and 0.01 is studied in this work. The cell parameters were obtained at laboratory temperature using XRD spectroscopy. The hyperfine parameters were measured at a 181Ta probe in the B site using Perturbed Angular Correla-tions (PAC) spectroscopy as a function of both temperature and composition. As a common trend, a static asymmetric and distributed quadrupolar interaction, strongly dependent on composition has been observed. The results, together with those corresponding to 1 > x ≥ 0.75, are analyzed using the point-charge model in terms of polarized oxygen vacancies, different covalence of the Ti-0 and Hf-0 bonds with computational simulation for the lattice positions of cations and oxygen vacancies.

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Crystal structure of high-spin tetraaquabis(2-chloropyrazine-κN4)iron(II) bis(4-methylbenzenesulfonate)

Acta Crystallographica Section E Crystallographic Communications ◽

10.1107/s2056989015010713 ◽

2015 ◽

Vol 71 (7) ◽

pp. 776-778

Author(s):

Bohdan O. Golub ◽

Sergii I. Shylin ◽

Sebastian Dechert ◽

Maria L. Malysheva ◽

Il`ya A. Gural`skiy

Keyword(s):

Crystal Structure ◽

Hydrogen Bonds ◽

High Spin ◽

Supramolecular Structure ◽

Complex Cation ◽

Point Group ◽

Three Dimensional ◽

Group Symmetry ◽

Point Group Symmetry ◽

Π Interactions

The title salt, [FeII(C4H3ClN2)2(H2O)4](C7H7O3S)2, contains a complex cation with point group symmetry 2/m. The high-spin FeIIcation is hexacoordinated by four symmetry-related water and twoN-bound 2-chloropyrazine molecules in atransarrangement, forming a distorted FeN2O4octahedron. The three-dimensional supramolecular structure is supported by intermolecular O—H...O hydrogen bonds between the complex cations and tosylate anions, and additional π–π interactions between benzene and pyrazine rings. The methyl H atoms of the tosylate anion are equally disordered over two positions.

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The influence of Bi content on dielectric properties of Bi4–xTi3O12–1.5x ceramics

Journal of Advanced Dielectrics ◽

10.1142/s2010135x17500217 ◽

2017 ◽

Vol 07 (03) ◽

pp. 1750021 ◽

Cited By ~ 1

Author(s):

Hui Gong ◽

Xiying Ke ◽

Shuqin Yang ◽

Zhaozhi Li ◽

Huyin Su ◽

...

Keyword(s):

Dielectric Constant ◽

Grain Size ◽

Curie Temperature ◽

Dielectric Materials ◽

Layered Perovskite ◽

Low Loss ◽

Solid State Method ◽

Spectra Analysis ◽

Perovskite Type ◽

Perovskite Type Structure

A kind of lead-free dielectric materials, such as the bismuth layered perovskite-type structure of Bi[Formula: see text]Ti3O[Formula: see text], was prepared by the conventional solid-state method at 800[Formula: see text]C and sintered at 1100[Formula: see text]C. The variation of structure and electrical properties with different Bi concentration was studied. All the Bi[Formula: see text]Ti3O[Formula: see text] samples exhibited a single structured phase. SEM could be a better approach to present the microstructure of Bi[Formula: see text]Ti3O[Formula: see text] ceramics. It could be found that the grain size of Bi[Formula: see text]Ti3O[Formula: see text] sintered at 1100[Formula: see text]C was smaller than that of others among the five samples through grain size mechanics. Through impedance spectra analysis, we knew, when the Bi content was fixed, that the dielectric constant and the loss values increased with the decrease of frequency. The Curie temperature of the five samples was about 670[Formula: see text]C. In particular, while at the frequency of 100[Formula: see text]kHz, the lowest loss was 0.001 when Bi content was 3.98. The Bi[Formula: see text]Ti3O[Formula: see text] ceramics with the minimum grain size had highest dielectric constant and the relatively low loss. Due to its high Curie temperature, high permittivity and low loss, the Bi4Ti3O[Formula: see text] (BIT) ceramics have a broad application prospect in high density memory, generator, sensor, ferroelectric tunnel junctions and so on.

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