scholarly journals Symmetry of diffraction patterns of two-dimensional crystal structures

2021 ◽  
pp. 113336
Author(s):  
Tatiana Latychevskaia ◽  
Recep Zan ◽  
Sergey Morozov ◽  
Kostya S. Novoselov
Keyword(s):  
Crystal Structures ◽  
Two Dimensional ◽  
Diffraction Patterns ◽  
Dimensional Crystal

Structures of the ZrZn22 family: suprapolyhedral nanoclusters, methods of self-assembly and superstructural ordering

2009 ◽  
Vol 65 (3) ◽  
pp. 300-307 ◽  
Author(s):  
G. D. Ilyushin ◽  
V. A. Blatov
Keyword(s):  
Crystal Structures ◽  
Self Assembly ◽  
Topological Analysis ◽  
Three Dimensional ◽  
Topological Type ◽  
Point Symmetry ◽  
Two Dimensional ◽  
The Matrix ◽  
Nanocluster Precursor ◽  
Dimensional Crystal

A combinatorial topological analysis is carried out by means of the program package TOPOS4.0 [Blatov (2006), IUCr Comput. Commun. Newsl. 7, 4–38] and the matrix self-assembly is modeled for crystal structures of the ZrZn22 family (space group Fd\bar 3m, Pearson code cF184), including the compounds with superstructural ordering. A number of strict rules are proposed to model the crystal structures of intermetallics as a network of cluster precursors. According to these rules the self-assembly of the ZrZn22-like structures was considered within the hierarchical scheme: primary polyhedral cluster → zero-dimensional nanocluster precursor → one-dimensional primary chain → two-dimensional microlayer → three-dimensional microframework (three-dimensional supraprecursor). The suprapolyhedral cluster precursor AB 2 X 37 of diameter ∼ 12 Å and volume ∼ 350 Å3 consists of three polyhedra (one AX 16 of the \bar 43m point symmetry and two regular icosahedra BX 12 of the \bar 3m point symmetry); the packing of the clusters determines the translations in the resulting crystal structure. A novel topological type of the two-dimensional crystal-forming 4,4-coordinated binodal net AB 2, with the Schläfli symbols 3636 and 3366 for nodes A and B, is discovered. It is shown that the ZrZn22 superstructures are formed by substituting some atoms in the cluster precursors. Computer analysis of the CRYSTMET and ICSD databases shows that the cluster AB 2 X 37 occurs in 111 intermetallics belonging to 28 structure types.

The generation of possible crystal structures of primary amides

1983 ◽  
Vol 388 (1794) ◽  
pp. 133-175 ◽  
Keyword(s):  
Crystal Structures ◽  
Van Der Waals ◽  
Three Dimensional ◽  
Close Packing ◽  
Two Dimensional ◽  
Coulomb Interactions ◽  
Primary Amide ◽  
Size And Shape ◽  
Dimensional Crystal ◽  
Hydrogen Bonded

Procedures are outlined for generation of crystal structures of primary amide molecules by constructing the possible ways in which the molecules may pack. For each given one- or two-dimensional hydrogen-bonded array, ensembles of three-dimensional crystal structures are generated by considering the possible ways in which the arrays may be juxtaposed. Observed and generated hypothetical molecular arrangements are analysed to highlight both favourable and unfavourable features, par­ticularly in terms of close packing principles, the size and shape of the molecule, van der Waals and Coulomb interactions and N-H ∙ ∙ ∙ O bonding geometry.

scholarly journals Metastability relationship between two- and three-dimensional crystal structures: a case study of the Cu-based compounds

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shota Ono
Keyword(s):  
Crystal Structures ◽  
Three Dimensional ◽  
Building Blocks ◽  
Two Dimensional ◽  
3D Structures ◽  
Metallic Element ◽  
Computational Materials ◽  
Dynamics Simulations ◽  
Dimensional Crystal

AbstractSome of the three-dimensional (3D) crystal structures are constructed by stacking two-dimensional (2D) layers. To study whether this geometric concept, i.e., using 2D layers as building blocks for 3D structures, can be applied to computational materials design, we theoretically investigate the dynamical stability of copper-based compounds CuX (a metallic element X) in the B$$_h$$ h and L1$$_1$$ 1 structures constructed from the buckled honeycomb (BHC) structure and in the B2 and L1$$_0$$ 0 structures constructed from the buckled square (BSQ) structure. We demonstrate that (i) if CuX in the BHC structure is dynamically stable, those in the B$$_h$$ h and L1$$_1$$ 1 structures are also stable. Using molecular dynamics simulations, we particularly show that CuAu in the B$$_h$$ h and L1$$_1$$ 1 structures withstand temperatures as high as 1000 K. Although the interrelationship of the metastability between the BSQ and the 3D structures (B2 and L1$$_0$$ 0 ) is not clear, we find that (ii) if CuX in the B2 (L1$$_0$$ 0 ) structure is dynamically stable, that in the L1$$_0$$ 0 (B2) is unstable. This is rationalized by the tetragonal Bain path calculations.

scholarly journals Simulation of electron density maps for two-dimensional crystal structures usingMathematica

2001 ◽  
Vol 34 (5) ◽  
pp. 658-660 ◽  
Author(s):  
Plinio Delatorre ◽  
Walter Filgueira de Azevedo Jr
Keyword(s):  
Crystal Structures ◽  
Electron Density ◽  
Two Dimensional ◽  
Thermal Displacement ◽  
Density Maps ◽  
Cell Dimensions ◽  
Unit Cell Dimensions ◽  
The Relationship ◽  
Dimensional Crystal

The simulations presented here are based on the programMathematicaas a tool to present electron density maps of two-dimensional crystal structures. The models give further insights into the relationship between the thermal displacement parameters and the quality of the electron density maps. Furthermore, users can readily test the effects of several crystallographic parameters on the electron density maps, such as, the number of reflections, the thermal displacement parameters and the unit-cell dimensions.

scholarly journals SVAT4: a computer program for visualization and analysis of crystal structures

2020 ◽  
Vol 53 (3) ◽  
pp. 848-853
Author(s):  
X.-Z. Li
Keyword(s):  
Computer Program ◽  
Crystal Structures ◽  
Magnetic Moments ◽  
Three Dimensional ◽  
Data File ◽  
Software Suite ◽  
Wide Range ◽  
Range Of Functions ◽  
Diffraction Patterns ◽  
Dimensional Crystal

SVAT4 is a computer program for interactive visualization of three-dimensional crystal structures, including chemical bonds and magnetic moments. A wide range of functions, e.g. revealing atomic layers and polyhedral clusters, are available for further structural analysis. Atomic sizes, colors, appearance, view directions and view modes (orthographic or perspective views) are adjustable. Customized work for the visualization and analysis can be saved and then reloaded. SVAT4 provides a template to simplify the process of preparation of a new data file. SVAT4 can generate high-quality images for publication and animations for presentations. The usability of SVAT4 is broadened by a software suite for simulation and analysis of electron diffraction patterns.

Parametric Approach To Predicting Two-Dimensional Crystal Structures

2003 ◽  
Vol 3 (4) ◽  
pp. 453-465 ◽  
Author(s):  
Scott W. Gordon-Wylie ◽  
George R. Clark
Keyword(s):  
Crystal Structures ◽  
Two Dimensional ◽  
Parametric Approach ◽  
Dimensional Crystal
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