Simple model designed to generate new crystal structures derived from a mother phase; application to molecular compounds

2002 ◽  
Vol 58 (4) ◽  
pp. 662-672 ◽  
Author(s):  
Claire Gervais ◽  
Gérard Coquerel
Keyword(s):  
Crystal Structure ◽  
Simple Model ◽  
Three Dimensional ◽  
Second Step ◽  
Two Dimensional ◽  
Basic Principles ◽  
Space Groups ◽  
Step Procedure ◽  
Symmetry Operators ◽  
Molecular Compounds

The basic principles of a model predicting new lattices from a known crystal structure are described. The first of the two-step procedure consists of extracting one- or two-dimensional periodic fragments (PF) from the mother structure. In the second step, symmetry operators are added to the PFs in order to generate one or several new three-dimensional lattices consistent with the 230 space groups. Most of the examples are related to polymorphism, but relationships between racemic compounds and enantiomers, twinning and lamellar epitaxy phenomena are also exemplified.

Seismic Behavior of some Basilica Churches after L’Aquila 2009 Earthquake

2010 ◽  
Vol 133-134 ◽  
pp. 801-806 ◽  
Author(s):  
Giuseppe Lucibello ◽  
Giuseppe Brandonisio ◽  
Elena Mele ◽  
Antonello De Luca
Keyword(s):  
Seismic Response ◽  
Case Studies ◽  
Seismic Behavior ◽  
Similar Case ◽  
Three Dimensional ◽  
Linear Analysis ◽  
Second Step ◽  
Two Dimensional ◽  
Step Procedure ◽  
Observed Damage

In this paper the seismic response of four church buildings in the l’Aquila April 2009 earthquake is analyzed. The buildings are: St. Giusta church, St. Maria di Collemaggio Basilica, St. Silvestro church and St. Pietro di Coppito church. The analyses are carried out by employing a “two-step” procedure suggested by the authors and already applied to similar case studies. The first step consists in three-dimensional linear analysis, while in the second step, two-dimensional non-linear analyses of macro-elements are carried out. The results coming from the two-steps, allow for understanding the observed damage and for approximately assessing the seismic level of the building.

scholarly journals From space to superspace and back: Superspace Group Finder

2008 ◽  
Vol 41 (6) ◽  
pp. 1182-1186 ◽  
Author(s):  
Ivan Orlov ◽  
Lukas Palatinus ◽  
Gervais Chapuis
Keyword(s):  
Crystal Structure ◽  
Dimensional Space ◽  
Flexible Structures ◽  
Three Dimensional ◽  
Real Space ◽  
Space Group ◽  
Space Groups ◽  
Group A ◽  
Modular Composition ◽  
Three Dimensional Space

The symmetry of a commensurately modulated crystal structure can be described in two different ways: in terms of a conventional three-dimensional space group or using the superspace concept in (3 +d) dimensions. The three-dimensional space group is obtained as a real-space section of the (3 +d) superspace group. A complete network was constructed linking (3 + 1) superspace groups and the corresponding three-dimensional space groups derived from rational sections. A database has been established and is available at http://superspace.epfl.ch/finder/. It is particularly useful for finding common superspace groups for various series of modular (`composition-flexible') structures and phase transitions. The use of the database is illustrated with examples from various fields of crystal chemistry.

scholarly journals Crystal structure ofcatena-poly[bis(formato-κO)bis[μ2-1,1′-(1,4-phenylene)bis(1H-imidazole)-κ2N3:N3′]cobalt(II)]

2015 ◽  
Vol 71 (9) ◽  
pp. m156-m157
Author(s):  
Guo-Wang Xu ◽  
Ye-Nan Wang ◽  
Hong-Xu Xia ◽  
Zhong-Long Wang
Keyword(s):  
Crystal Structure ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Supramolecular Network ◽  
Nitrate Hexahydrate ◽  
Coordination Geometry ◽  
Two Dimensional ◽  
Asymmetric Unit ◽  
Hydrogen Bonding Interactions ◽  
Block Shaped Crystal

A red block-shaped crystal of the title compound, [Co(HCOO)2(C12H10N4)2]n, was obtained by the reaction of cobalt(II) nitrate hexahydrate, formic acid and 1,1′-(1,4-phenylene)bis(1H-imidazole) (bib) molecules. The asymmetric unit consists of one CoIIcation, one formate ligand and two halves of a bib ligand. The central CoIIcation, located on an inversion centre, is coordinated by two carboxylate O atoms and four N atoms from bib ligands, completing an octahedral coordination geometry. The CoIIcentres are bridged by bib ligands, giving a two-dimensional net. Topologically, taking the CoIIatoms as nodes and the bib ligands as linkers, the two-dimensional structure can be simplified as a typicalsql/Shubnikov tetragonal plane network. The structure features C—H...O hydrogen-bonding interactions between formate and bib ligands, resulting in a three-dimensional supramolecular network.

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.

Relationship of the nanocrystal morphology and atomistic structure with respect to the superstructure ordering within PbS- and Gold-Mesocrystals

2014 ◽  
Vol 1705 ◽  
Author(s):  
Lydia Bahrig ◽  
Danny Haubold ◽  
Falk Röder ◽  
Stephen G. Hickey ◽  
Alexander Eychmüller
Keyword(s):  
Crystal Structure ◽  
Structure Formation ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Relationship Of ◽  
The Relationship ◽  
Atomistic Structure

ABSTRACTThe relationship between nanoparticle geometry and their two dimensional assembly is investigated in order to provide insights into the three dimensional arrangement of mesocrystals. The crystal structure of the nanoparticles and their homogeneity are investigated during structure formation on the mesoscale whereby effects such as fibrillation have been observed.

scholarly journals Crystal structure of poly[μ2-aqua-aqua(μ2-4-nitro-2,5,6-trioxo-1,2,5,6-tetrahydropyridin-3-olato)hemi-μ4-oxalato-barium(II)]

2015 ◽  
Vol 71 (5) ◽  
pp. 459-462 ◽  
Author(s):  
Rusul Alabada ◽  
Olga Kovalchukova ◽  
Irina Polyakova ◽  
Svetlana Strashnova ◽  
Vladimir Sergienko
Keyword(s):  
Crystal Structure ◽  
Coordination Polymer ◽  
Hydrogen Bonds ◽  
Three Dimensional ◽  
Water Molecules ◽  
Two Dimensional ◽  
Supramolecular Framework ◽  
Screw Axis ◽  
Bond Lengths ◽  
Chelate Rings

In the title coordination polymer, [Ba(C5HN2O6)(C2O4)0.5(H2O)2]n, the tenfold coordination of the Ba centre consists of four O atoms from the two 4-nitro-2,5,6-trioxo-1,2,5,6-tetrahydropyridin-3-olate (L) anions, three O atoms of two oxalate anions and three water molecules. The Ba—O bond lengths fall in the range 2.698 (3)–2.978 (3) Å. TheLligand chelates two Ba atoms related by a screw axis, leading to formation of fused five- and six-membered chelate rings. Due to the bridging function of the ligands and water molecules, the complex monomers are connected into polymeric two-dimensional layers parallel to thebcplane. Intermolecular O—H...O hydrogen bonds link these layers into a three-dimensional supramolecular framework.

Diaquabis(dicyanamido)bis[4-(2-pyridyl)-4H-1,2,4-triazole-κN 1]cobalt(II)

2006 ◽  
Vol 62 (7) ◽  
pp. m1479-m1481 ◽  
Author(s):  
Yu-Hong Ma ◽  
Pi-Zhuang Ma ◽  
Huan-Qin Zhu ◽  
Chang-Cheng Liu
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Three Dimensional ◽  
Title Complex ◽  
Water Molecules ◽  
Two Dimensional ◽  
Complex Molecules ◽  
Dimensional Network

The title complex, [Co(C2N3)2(C7H6N4)2(H2O)2] or [Co(dca)2(pytrz)2(H2O)2], where pytrz is 4-(2-pyridyl)-4H-1,2,4-triazole and dca is the dicyanamide monoanion, was prepared using pytrz, Na(dca) and CoCl2·6H2O. The CoII atom lies on a center of inversion and is coordinated in a slightly distorted octahderal geometry by two pytrz ligands, two dca ligands and two trans-oriented water molecules. In the crystal structure, complex molecules are linked by O—H...N hydrogen bonds into a two-dimensional network and further into a three-dimensional network via weak C—H...N hydrogen bonds.

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