scholarly journals Geometrical prediction of cleavage planes in crystal structures

IUCrJ ◽  
2021 ◽  
Vol 8 (5) ◽  
Author(s):  
Uriel Vaknin ◽  
Dov Sherman ◽  
Semën Gorfman
Keyword(s):  
Crystal Structures ◽  
Theoretical Calculations ◽  
Three Dimensional ◽  
Geometrical Approach ◽  
Two Dimensional ◽  
Average Electron Density ◽  
Inorganic Crystal ◽  
Cleavage Energy ◽  
Lattice Planes ◽  
Average Electron

Cleavage is the ability of single crystals to split easily along specifically oriented planes. This phenomenon is of great interest for materials' scientists. Acquiring the data regarding cleavage is essential for the understanding of brittle fracture, plasticity and strength, as well as for the prevention of catastrophic device failures. Unfortunately, theoretical calculations of cleavage energy are demanding and often unsuitable for high-throughput searches of cleavage planes in arbitrary crystal structures. A simplified geometrical approach (GALOCS = gaps locations in crystal structures) is suggested for predicting the most promising cleavage planes. GALOCS enumerates all the possible reticular lattice planes and calculates the plane-average electron density as a function of the position of the planes in the unit cell. The assessment of the cleavage ability of the planes is based on the width and depth of planar gaps in crystal structures, which appear when observing the planes lengthwise. The method is demonstrated on two-dimensional graphene and three-dimensional silicon, quartz and LiNbO3 structures. A summary of planar gaps in a few more inorganic crystal structures is also presented.

Synthesis, Crystal Structure, and Theoretical Calculations of Two Cobalt, Nickel Coordination Polymers with 5-Nitroisophthalic Acid and Bis(imidazol) Ligands

2016 ◽  
Vol 69 (11) ◽  
pp. 1296 ◽  
Author(s):  
Ya-Ru Pan ◽  
Xiu-Mei Li ◽  
Jian-Ye Ji ◽  
Qing-Wei Wang
Keyword(s):  
Theoretical Calculations ◽  
Uv Spectroscopy ◽  
Three Dimensional ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
Cobalt Nickel ◽  
Hydrogen Bonding Interactions ◽  
Calculation Results ◽  
Covalent Interactions ◽  
2D Network

Two new complexes [Co(NIPH)(bimb)(H2O)]n (1) and [Ni(NIPH)(mbix)]n (2) (H2NIPH = 5-nitroisophthalic acid, bimb = 1,4-bis(imidazol-1-yl)butane, mbix = 1,3-bis(imidazol-1-ylmethyl)benzene) have been hydrothermally synthesised and structurally characterised by elemental analysis, IR spectroscopy, thermogravimetric analysis, UV spectroscopy, and single-crystal X-ray diffraction. Complex 1 exhibits a two-dimensional (2D) network, which was stabilised through O–H···O and C–H···O hydrogen-bonding interactions. Complex 2 shows a two-dimensional (2D) network structure, which was further extended into a three-dimensional supramolecular structure through C–H···O hydrogen bonds and π–π interactions. Moreover, we analysed the natural bond orbital (NBO) using the PBE0/LANL2DZ method in the Gaussian 03 program. The calculation results indicated the obvious covalent interactions between the coordinated atoms and the CoII or NiII ion.

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.

scholarly journals Crystal structures of tetramethylammonium (2,2′-bipyridine)tetracyanidoferrate(III) trihydrate and poly[[(2,2′-bipyridine-κ2N,N′)di-μ2-cyanido-dicyanido(μ-ethylenediamine)(ethylenediamine-κ2N,N′)cadmium(II)iron(II)] monohydrate]

2016 ◽  
Vol 72 (5) ◽  
pp. 741-746
Author(s):  
Songwuit Chanthee ◽  
Wikorn Punyain ◽  
Supawadee Namuangrak ◽  
Kittipong Chainok
Keyword(s):  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Layer Structure ◽  
Three Dimensional ◽  
Building Blocks ◽  
Chain Structure ◽  
Water Molecules ◽  
Two Dimensional ◽  
Lattice Water ◽  
Π Stacking

The crystal structures of the building block tetramethylammonium (2,2′-bipyridine-κ2N,N′)tetracyanidoferrate(III) trihydrate, [N(CH3)4][Fe(CN)4(C10H8N2)]·3H2O, (I), and a new two-dimensional cyanide-bridged bimetallic coordination polymer, poly[[(2,2′-bipyridine-κ2N,N′)di-μ2-cyanido-dicyanido(μ-ethylenediamine-κ2N:N′)(ethylenediamine-κ2N,N′)cadmium(II)iron(II)] monohydrate], [CdFe(CN)4(C10H8N2)(C2H8N2)2]·H2O, (II), are reported. In the crystal of (I), pairs of [Fe(2,2′-bipy)(CN)4]−units (2,2′-bipy is 2,2′-bipyridine) are linked together through π–π stacking between the pyridyl rings of the 2,2′-bipy ligands to form a graphite-like structure parallel to theabplane. The three independent water molecules are hydrogen-bonded alternately with each other, forming a ladder chain structure withR44(8) andR66(12) graph-set ring motifs, while the disordered [N(CH3)4]+cations lie above and below the water chains, and the packing is stabilized by weak C—H...O hydrogen bonds. The water chains are further linked with adjacent sheets into a three-dimensional networkviaO—H...O hydrogen bonds involving the lattice water molecules and the N atoms of terminal cyanide groups of the [Fe(2,2′-bipy)(CN)4]−building blocks, forming anR44(12) ring motif. Compound (II) features a two-dimensional {[Fe(2,2′-bipy)(CN)4Cd(en)2]}nlayer structure (en is ethylenediamine) extending parallel to (010) and constructed from {[Fe(2,2′-bipy)(CN)4Cd(en)]}nchains interlinked by bridging en ligands at the Cd atoms. Classical O—H...N and N—H...O hydrogen bonds involving the lattice water molecule and N atoms of terminal cyanide groups and the N—H groups of the en ligands are observed within the layers. The layers are further connectedviaπ–π stacking interactions between adjacent pyridine rings of the 2,2′-bipy ligands, completing a three-dimensional supramolecular structure.

Isostructurality in one and two dimensions: isostructurality of polymorphs

2004 ◽  
Vol 60 (5) ◽  
pp. 547-558 ◽  
Author(s):  
László Fábián ◽  
Alajos Kálmán
Keyword(s):  
Crystal Structures ◽  
Three Dimensional ◽  
Two Dimensions ◽  
Cambridge Structural Database ◽  
Two Dimensional ◽  
Structural Database ◽  
Specific Packing ◽  
Packing Interactions

A set of polymorphic crystal structures was retrieved from the Cambridge Structural Database in order to estimate the frequency of isostructurality among polymorphs. Altogether, 50 structures, the polymorphs of 22 compounds, were investigated. It was found that one-, two- or three-dimensional isostructurality is exhibited by approximately half of the compounds analyzed. Among the isostructural polymorphs, the frequency of one-, two- and three-dimensional isostructurality is similar. From the examples, it appears that three-dimensional isostructurality is connected to the gradual ordering of crystal structures, while one- and two-dimensional isostructurality can often be related to specific packing interactions. The possibility of many similar interactions seems to decrease the probability of the occurrence of isostructural polymorphs. Conformational polymorphs do not exhibit isostructurality.

scholarly journals Two-Dimensional Clusters of Colloidal Particles Induced by Emulsion Droplet Evaporation

Nanomaterials ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 156 ◽  
Author(s):  
Hai Pham-Van ◽  
Linh Tran-Phan-Thuy ◽  
Cuong Tran-Manh ◽  
Bich Do-Danh ◽  
Hoang Luc-Huy
Keyword(s):  
Colloidal Particles ◽  
Three Dimensional ◽  
Droplet Evaporation ◽  
Dimensional System ◽  
Geometrical Approach ◽  
Two Dimensional ◽  
Emulsion Droplet ◽  
Second Moment ◽  
Minimization Principle ◽  
Metropolis Monte Carlo

The minimization principle of the second moment of the mass distribution ( M 2 ) is responsible for the unique structure of three-dimensional clusters by using emulsion droplet evaporation. Herein we study the structure of two-dimensional clusters of colloidal particles bound at the interface of liquid droplets in the plane. We found that, differently from the three-dimensional system, the two-dimensional clusters have multiple degenerate configurations (isomers). An interesting feature of such two-dimensional clusters is that they have the same packings as those belonging to a class of geometric figures known as polyiamonds. In particular, except for the six-particle cluster, many higher order clusters of polyiamond have not been reported previously. Using a simple geometrical approach, based on the number of ways to generate a packing, we calculated the occupation probabilities of distinct isomeric clusters. The level of agreement with the results of metropolis Monte Carlo simulations was good for clusters containing up to nine particles, suggesting that our two-dimensional cluster structures are not a result of the minimization of the second moment. In addition, the structure of these clusters is somewhat insensitive to the range and depth of the interparticle potential, in good agreement with the results in the literature.

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 Structure and Stability of B10N14: Cages, Sheets, and Rings

2019 ◽  
Vol 2019 ◽  
pp. 1-5
Author(s):  
Melanie Walker ◽  
Kelvin Jones ◽  
DaiQuan Noble ◽  
Marquavias Walker ◽  
Douglas L. Strout
Keyword(s):  
Density Functional Theory ◽  
Boron Nitride ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Three Dimensional ◽  
Basis Sets ◽  
Molecular Forms ◽  
Two Dimensional ◽  
Functional Theory ◽  
Structure And Stability

Boron nitride is a material similar to carbon in its ability to adopt numerous molecular forms, including two-dimensional sheets and three-dimensional cages and nanotubes. Boron nitride single molecules, such as B12N12, have isomeric forms that include rings and sheets, as well as cage forms analogous and isoelectronic to the carbon fullerenes. Such cages tend to be composed of squares and hexagons to allow perfect alternation of boron and nitrogen atoms, which is possible because of the 1 : 1 ratio of boron-to-nitrogen atoms. What about molecules in which this 1 : 1 ratio does not apply? In the current study, theoretical calculations are carried out on molecules of B10N14 to determine energetically favorable isomers. Density functional theory is used in conjunction with Dunning basis sets. Cage, sheet, and ring isomers are considered. Energetic trends are calculated and discussed, in comparison to comparable studies on B12N12.

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