Über Oxidpnictide: Zur Kenntnis von A2Mn3B2O2 mit A = Sr, Ba und B = As, Sb, Bi / On Oxidpnictides: Preparation and Crystal Structure of A2Mn3B2O2 with A = Sr, Ba and B = As, Sb, Bi

1979 ◽  
Vol 34 (6) ◽  
pp. 777-780 ◽  
Author(s):  
Erwin Brechtel ◽  
Gerhard Cordier ◽  
Herbert Schäfer
Keyword(s):  
Crystal Structure ◽  
Double Layers ◽  
Two Dimensional ◽  
Tetragonal System

Five new oxidpnictides have been prepared and structurally characterized. They crystallize in the tetragonal system, I4/mmm, with the following constants: Sr2Mn3As2O2: a = 416 ± 1 pm, c = 1884 ± 4 pm, c/a = 4.529, Ba2Mn3As2O2 : a = 424.8 ± 0 5 pm, c = 1977 ± 3 pm, c/a = 4.654, Sr2Mn3Sb2O2 : a = 426.2 ± 0.4 pm, c = 2011 ± 2 pm, c/a = 4.718, Ba2Mn3Sb2O2 : a = 436.7 ± 0.5 pm, c = 2078 ± 2 pm, c/a = 4.758, Sr2Mn3Bi2O2 : a = 428 ± 1 pm, c = 2055 ± 5 pm, c/a = 4.801. Mn- and As(Sb,Bi) atoms form tetragonal pyramids, connected by common edges in the basis to two-dimensional sheets. These sheets are separated by double layers of Sr atoms, in which Mn and O atoms are located forming MnO4 square plane nets.

Zur Darstellung und Struktur von CaMnBi2 / On the Preparation and Crystal Structure of CaMnBi2

1980 ◽  
Vol 35 (1) ◽  
pp. 1-3 ◽  
Author(s):  
Erwin Brechtel ◽  
Gerhard Cordier ◽  
Herbert Schäfer
Keyword(s):  
Crystal Structure ◽  
Double Layers ◽  
Two Dimensional ◽  
Space Group ◽  
System A ◽  
Tetragonal System

Abstract The new compound CaMnBi2 has been analytically and structurally characterized. CaMnBi2 crystallizes in the tetragonal system (a = 450 ± 1 pm, c = 1108 ± 2 pm, space group P4/nmm). Mn and Bi atoms form fourfold pyramids, connected by common edges in the basis to two-dimensional sheets. These sheets are separated by double layers of Ca atoms between which further Bi atoms are located forming squarenets. The structure is strongly related to that of SrZnSb2 which can be interpreted as a distorted variant of the new CaMnBi2 type.

Two-dimensional zeolite-like network in the new caesium copper aluminate Cs2CuAl4O8

2015 ◽  
Vol 71 (5) ◽  
pp. 498-506 ◽  
Author(s):  
Larisa Shvanskaya ◽  
Olga Yakubovich ◽  
Werner Massa ◽  
Alexander Vasiliev
Keyword(s):  
Crystal Structure ◽  
Three Dimensional ◽  
Double Layers ◽  
Two Dimensional ◽  
Magnetic Subsystem ◽  
Jahn Teller ◽  
Copper Aluminate ◽  
Jahn Teller Effect ◽  
Phosphate Flux ◽  
Temperature Crystallization

Monoclinic dicaesium copper tetraaluminate, Cs2CuAl4O8, space groupP21/c,a= 8.4551 (7),b= 10.012 (1),c= 17.073 (2) Å, β = 101.643 (9)°,Z= 6, was obtained by high-temperature crystallization from a phosphate flux. Its microporous crystal structure presents the first example of double layers built from [AlO4] tetrahedra combined in 4-, 6- and 8-rings, topologically similar to those found in theATT-type zeolites and isostructural minerals armstrongite, davanite and dalyite. These layers show a rare arrangement of three [AlO4] tetrahedra sharing one oxygen vertex. The aluminate slabs are further linked by chains of edge-sharing [CuO4] square planes to form a mixed anionic three-dimensional framework with Cs+cations in channels and cavities. An unusually short Cu...Cs distance of 3.166 Å is ascribed to the strong Jahn–Teller effect of Cu2+. The magnetic subsystem demonstrates properties of an alternating antiferromagnetic chain with a gap in the spectrum of magnetic excitations.

Zur Darstellung und Kristallstruktur des SrZnSb2 / On the Preparation and Crystal Structure of SrZnSb2

1979 ◽  
Vol 34 (2) ◽  
pp. 251-255 ◽  
Author(s):  
Erwin Brechtel ◽  
Gerhard Cordier ◽  
Herbert Schäfer
Keyword(s):  
Crystal Structure ◽  
Double Layers ◽  
Two Dimensional ◽  
Orthorhombic System

Abstract SrZnSb2 has been prepared and characterized analytically and structurally. The compound crystallizes in the orthorhombic system with a = 2305 ± 5 pm, b = 437 ± 1 pm, c = 446 ± 1 pm, Pnma-D2h16. Zn- and Sb-atoms form distorted fourfold pyramids, connected by common edges in the basis to two-dimensional sheets. These sheets are separated by double layers of Sr-atoms in which further Sb-atoms are located building four-cornered networks.

scholarly journals 1-Ethyl 2-methyl 3,4-bis(acetyloxy)pyrrolidine-1,2-dicarboxylate: crystal structure, Hirshfeld surface analysis and computational chemistry

2020 ◽  
Vol 76 (6) ◽  
pp. 967-972 ◽  
Author(s):  
Sofia Dallasta Pedroso ◽  
Ignez Caracelli ◽  
Julio Zukerman-Schpector ◽  
Monica Soto-Monsalve ◽  
Regina H. De Almeida Santos ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hirshfeld Surface ◽  
Double Layers ◽  
Equatorial Position ◽  
Two Dimensional ◽  
Energy Term ◽  
Pyrrolidine Ring ◽  
Dispersion Energy ◽  
Compound C ◽  
Layer Region

The title compound, C13H19NO8, is based on a tetra-substituted pyrrolidine ring, which has a twisted conformation about the central C—C bond; the Cm—Ca—Ca—Cme torsion angle is 38.26 (15)° [m = methylcarboxylate, a = acetyloxy and me = methylene]. While the N-bound ethylcarboxylate group occupies an equatorial position, the remaining substituents occupy axial positions. In the crystal, supramolecular double-layers are formed by weak methyl- and methylene-C—H...O(carbonyl) interactions involving all four carbonyl-O atoms. The two-dimensional arrays stack along the c axis without directional interactions between them. The Hirshfeld surface is dominated by H...H (55.7%) and H...C/C...H (37.0%) contacts; H...H contacts are noted in the inter-double-layer region. The interaction energy calculations point to the importance of the dispersion energy term in the stabilization of the crystal.

Crystal structure of pomalidomide Form I, C13H11N3O4

2021 ◽  
pp. 1-6
Author(s):  
James A. Kaduk ◽  
Amy M. Gindhart ◽  
Thomas N. Blanton
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Powder Diffraction ◽  
Density Functional ◽  
Double Layers ◽  
Carbonyl Groups ◽  
Hydrogen Atoms ◽  
Powder Diffraction File ◽  
Functional Theory ◽  
Amine Hydrogen

The crystal structure of pomalidomide Form I has been solved and refined using synchrotron X-ray powder diffraction data and optimized using density functional theory techniques. Pomalidomide Form I crystallizes in the space group P-1 (#2) with a = 7.04742(9), b = 7.89103(27), c = 11.3106(6) Å, α = 73.2499(13), β = 80.9198(9), γ = 88.5969(6)°, V = 594.618(8) Å3, and Z = 2. The crystal structure is characterized by the parallel stacking of planes parallel to the bc-plane. Hydrogen bonds link the molecules into double layers also parallel to the bc-plane. Each of the amine hydrogen atoms acts as a donor to a carbonyl group in an N–H⋯O hydrogen bond, but only two of the four carbonyl groups act as acceptors in such hydrogen bonds. Other carbonyl groups participate in C–H⋯O hydrogen bonds. The powder pattern has been submitted to ICDD® for inclusion in the Powder Diffraction File™ (PDF®).

scholarly journals Rational Design and Simulation of Two-Dimensional Perovskite Photonic Crystal Absorption Layers Enabling Improved Light Absorption Efficiency for Solar Cells

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2460
Author(s):  
Jian Zou ◽  
Mengnan Liu ◽  
Shuyu Tan ◽  
Zhijie Bi ◽  
Yong Wan ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solar Cells ◽  
Photonic Crystal ◽  
Incident Light ◽  
Absorption Efficiency ◽  
Utilization Efficiency ◽  
Photonic Crystal Structure ◽  
Two Dimensional ◽  
Photoelectric Conversion ◽  
Absorption Layer

A two-dimensional perovskite photonic crystal structure of Methylamine lead iodide (CH3NH3PbI3, MAPbI3) is rationally designed as the absorption layer for solar cells. The photonic crystal (PC) structure possesses the distinct “slow light” and band gap effect, leading to the increased absorption efficiency of the absorption layer, and thus the increased photoelectric conversion efficiency of the battery. Simulation results indicate that the best absorption efficiency can be achieved when the scattering element of indium arsenide (InAs) cylinder is arranged in the absorption layer in the form of tetragonal lattice with the height of 0.6 μm, the diameter of 0.24 μm, and the lattice constant of 0.4 μm. In the wide wavelength range of 400–1200 nm, the absorption efficiency can be reached up to 82.5%, which is 70.1% higher than that of the absorption layer without the photonic crystal structure. In addition, the absorption layer with photonic crystal structure has good adaptability to the incident light angle, presenting the stable absorption efficiency of 80% in the wide incident range of 0–80°. The results demonstrate that the absorption layer with photonic crystal structure can realize the wide spectrum, wide angle, and high absorption of incident light, resulting in the increased utilization efficiency of solar energy.

scholarly journals Crystal structure of two-dimensional coordination polymer poly-[μ2-azido-aqua-(μ2-pyrazine-2-carboxylato-κ3O,N:N′)nickel(II)], C5H5N5O3Ni

2016 ◽  
Vol 231 (4) ◽  
pp. 1163-1164
Author(s):  
Yu Youzhu ◽  
Guo Yuhua ◽  
Yang Liguo ◽  
Niu Yongsheng
Keyword(s):  
Crystal Structure ◽  
Coordination Polymer ◽  
Two Dimensional

AbstractC5H5N5O3Ni, monoclinic, C2/c (no. 15), a = 8.5804(17) Å, b = 13.790(3) Å, c = 13.969(3) Å, β = 104.37(3)°, V =1601.2(6)Å3, Z = 8, Rgt(F) = 0.0203, wRref(F2) = 0.0550, T = 293 K.

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