Topology: ToposPro

Блатов, В. А.; Alexandrov, Eugeny V.; Шевченко, А. П.

doi:10.1016/b978-0-12-409547-2.14576-7

Cited by 34 publications

(30 citation statements)

References 133 publications

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“…In addition to coordination sequences, ToposPro computes the so-called point symbols and vertex symbols that collect the shortest cycles and rings (cycles without shortcuts) of atoms, respectively. 28 The general scheme of the analysis includes the following steps: 29 (i) determination of all interatomic interactions in the structure using a number of chemical and geometrical criteria; (ii) search for structural groups (building blocks) with unique topological algorithms; (iii) simplication of the structure by squeezing the structural groups into their centers of mass keeping the connectivity between the groups; (iv) determination of the topology for the resulting underlying net, i.e. the net of the centers of the structural groups, by comparison of the topological indices (coordination sequences, point and vertex symbols) of the underlying net with the indices for the reference topologies from the ToposPro TTD Collection.…”

Section: Methodsmentioning

confidence: 99%

Nanoporous materials with predicted zeolite topologies

et al. 2020

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Section: Methodsmentioning

confidence: 99%

Nanoporous materials with predicted zeolite topologies

et al. 2020

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“…Among these 224 allotropes, 184 have topologies, which have never been found in crystal structures. When naming these topologies, we use the suffix "-CA" ("Carbon Allotrope") in addition to the standard ToposPro nDk name 12 . For example, the name 4,4,4T16-CA = 4 3 T16-CA means that this hypothetical carbon allotrope has three inequivalent 4-coordinated atoms, is threeperiodic, and is 16th in the set of other three-periodic hypothetical carbon allotropes with the same number of inequivalent fourcoordinated atoms.…”

Section: Generating Proceduresmentioning

confidence: 99%

“…Each topological region of the CS is characterized by the net A in the highest symmetry embedding; different points of the region corresponding to geometrical distortions of A. The names of the net topologies are given according to conventional nomenclatures 12 , the most widespread of which is the RCSR nomenclature of bold three-letter symbols (e.g., dia designates the diamond topology). This enables us to avoid slightly distorted copies of the same topology, which are often derived in the DFT generation.…”

Section: Topological Network Model Of Solid-state Transformationsmentioning

confidence: 99%

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High-throughput systematic topological generation of low-energy carbon allotropes

et al. 2021

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The search for new materials requires effective methods for scanning the space of atomic configurations, in which the number is infinite. Here we present an extensive application of a topological network model of solid-state transformations, which enables one to reduce this infinite number to a countable number of the regions corresponding to topologically different crystalline phases. We have used this model to successfully generate carbon allotropes starting from a very restricted set of initial structures; the generation procedure has required only three steps to scan the configuration space around the parents. As a result, we have obtained all known carbon structures within the specified set of restrictions and discovered 224 allotropes with lattice energy ranging in 0.16–1.76 eV atom−1 above diamond including a phase, which is denser and probably harder than diamond. We have shown that this phase has a quite different topological structure compared to the hard allotropes from the diamond polytypic series. We have applied the tiling approach to explore the topology of the generated phases in more detail and found that many phases possessing high hardness are built from the tiles confined by six-membered rings. We have computed the mechanical properties for the generated allotropes and found simple dependences between their density, bulk, and shear moduli.

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“…Topological nets (Blatov et al, 2014), constructed by replacing molecules with nodes and hydrogen bonds with edges, reduce the supramolecular complexity and can be used to understand similarities and differences between the compounds. Topological analysis of hydrogen bonds in (1)-(4) performed with ToposPro (Blatov & Shevchenko, 2019) revealed that all structures are better described as uninodal, but with different connectivity (see supporting information). Compound (1) forms a 14-connected net corresponding to the topological type bcu-x.…”

Section: Resultsmentioning

confidence: 99%

Crystal structure, vibrational frequencies and polarizability distribution in hydrogen-bonded salts of pyromellitic acid

Santos¹,

Krawczuk²,

Franco³

et al. 2020

Acta Crystallogr Sect B

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Structural features of moderate‐to‐strong O—H…O hydrogen bonds are related to the frequencies of O—H stretching vibrations and to the electric polarizability distribution in the donor and acceptor functional groups for crystals synthesized from the 1,2,4,5‐benzenetetracarboxylic (pyromellitic) acid, namely: bis(3‐aminopyridinium) dihydrogen pyromellitate tetrahydrate, (1); bis(3‐carboxypyridinium) dihydrogen pyromellitate, (2); bis(3‐carboxyphenylammonium) dihydrogen pyromellitate dihydrate, (3); and bis(4‐carboxyphenylammonium) dihydrogen pyromellitate, (4). A combination of single‐crystal X‐ray diffraction, powder Raman spectroscopy and first‐principle calculations in both crystalline and gaseous phases has shown that changes in the O—H…O hydrogen‐bond geometry can be followed by changes in the corresponding spectral modes. Vibrational properties of moderate hydrogen bonds can be estimated from correlations based on statistical analysis of several compounds [Novak (1974). Struct. Bond.18, 177–216]. However, frequencies related to very short O—H…O bonds can only be predicted by relationships built from a subset of structurally similar systems. Moreover, the way in which hydrogen bonds affect the polarizability of donor and acceptor groups depends on their strength. Moderate interactions enhance the polarizability and make it more anisotropic. Shorter hydrogen bonds may decrease the polarizability of a group as a consequence of the volume restraint implied by the neighbour molecule within a hydrogen‐bonded aggregate. This is significant for evaluation of the electric susceptibility in crystals and, therefore, for estimation of refractive indices and birefringence.

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Topology: ToposPro

Cited by 34 publications

References 133 publications

Nanoporous materials with predicted zeolite topologies

Nanoporous materials with predicted zeolite topologies

High-throughput systematic topological generation of low-energy carbon allotropes

Crystal structure, vibrational frequencies and polarizability distribution in hydrogen-bonded salts of pyromellitic acid

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