New statistical data on the topology of homomolecular organic crystals

Chernikova, N. Yu.; Bel'skii, V. K.; Zorkiĭ, P. M.

doi:10.1007/bf00752502

Cited by 35 publications

(20 citation statements)

References 6 publications

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“…There were 190 SC in Belsky & Zorky (1977) and 283 SC in Chemikova, Belsky & Zorky (1990). We noted (Chemikova, Belsky & Zorky, 1990) that the number of SC continued to grow fairly rapidly: 5-10 (on average about 7) new SC were discovered annually from 1974 to 1987.…”

Section: Resultsmentioning

confidence: 86%

“…It is curious that the share of this class slightly increases as years pass. However, the frequencies of occurence of 'giants' have changed very little compared with Chernikova, Belsky & Zorky (1990). This indicates that the volume of statistical data is sufficently large, and that these data adequately reflect the general picture of the structure of homomolecular crystals.…”

Section: Resultsmentioning

confidence: 96%

“…We noted (Chemikova, Belsky & Zorky, 1990) that the number of SC continued to grow fairly rapidly: 5-10 (on average about 7) new SC were discovered annually from 1974 to 1987. In the following five years, there appeared a trend towards the reduction of this number: about five new SC were added each year [authors of X-ray structural studies still do not notice the appearance of a new way of molecular arrangement in the crystal, although Chemikova, Belsky & Zorky (1990), as well as the present work, seem to offer such a possibility]. There are strong reasons to believe that, in the future, new SC will be found still more rarely.…”

Section: Resultsmentioning

confidence: 99%

“…The SC that have been added to the list of Chernikova, Belsky & Zorky (1990) are marked + (after the SC symbol), ambiguous symbols are marked * (before the SC symbol). The systemization of SC according to their occurence is reflected by means of marks prefixing the number of known representatives in the following way: !!…”

Section: Resultsmentioning

confidence: 99%

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Structural classes and space groups of organic homomolecular crystals: new statistical data

Belsky¹,

Zorkaya²,

Zorky³

1995

Acta Crystallogr A Found Crystallogr

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IntroductionStructural classes (SC) are very useful for the description and consideration of molecular arrangements in crystals. The distribution of 19642 organic homomolecular crystals among SC has been investigated. 305 SC having very unequal frequencies were discovered. A full list is given.© 1995 International Union of Crystallography Printed in Great Britain -all rights reservedThe concept of structural class (SC), proposed by Zorky, Belsky, Lazareva & Porai-Koshits (1967), has proved to be very convenient for describing the general features of molecular arrangements connected with space symmetry. We sometimes say that the SC reflects 'the topology' of a molecular crystal (Zorky 1991 (International Tables for X-ray Crystallography, 1974) is used here. By 'the molecule occupies a position', we mean that this position is occupied by a single point of the molecule, e.g. by the center of mass. Two distributions of molecules throughout orbits are, of course, not regarded as different SC if one of them can be transformed into another by transferring the origin or by renaming or changing the choice of coordinate axes (without violation of rules accepted in crystallography) (International Tables for X-ray Crystallography, 1974).We have more than once presented the statistical data on the SC of homomolecular organic crystals (Belsky & Zorky, 1970 Chemikova, Belsky & Zorky, 1990), considering as organic those substances that contain carbon and only the following elements: H, B, Si, N, P, As, O, S, Se, Te, F, C1, Br, I. Organometallic and very numerous chelate compounds have been excluded from consideration in order to limit the range of objects and thus to facilitate the solution of the problem.In essence, our aim was to reveal the general picture of the structure of organic crystals. It seems likely that the regularities established for organic substances would remain unaltered if the range of objects included molecular compounds of metals as well. At the same time, a substantial restriction lies in the fact that we have considered only homomolecular crystals, i.e. crystals formed by chemically identical molecules, and only such crystals will be dealt with below. The statistical investigations on heteromolecular crystals, and not only organic ones, has also been initiated (Chemikova & Zorky, 1979; Zorky & Chemikova, 1985) but has not reached the necessary level of completeness.A SC symbol includes a space group, a number of molecules per unit cell (Z) and an indication of the orbits occupied by molecules, these orbits being written in parentheses in the form of the point-group designations characterizing the symmetry of the positions. Molecules in the crystal most often occupy one orbit (monosystem crystals, k = 1), In this case, there is only one point group within the parentheses in the last part of the SC symbol, e.g. _C2/m, Z = 2(2/m), C2/m, Z = 4(m), P21/c, Z = 2(1), P2x/c, Z = 4(1). If molecules occupy k orbits (polysystem crystals), then the SC symbol includes k point-group symbols, e.g. the cl...

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Section: Resultsmentioning

confidence: 86%

Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Structural classes and space groups of organic homomolecular crystals: new statistical data

Belsky¹,

Zorkaya²,

Zorky³

1995

Acta Crystallogr A Found Crystallogr

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show abstract

“…It is well known that among the 230 space groups quite a small fraction is typical of organic crystals. It has been found that over 80% organic crystallines belong to 7 typical space groups (P2 1 /c, P-1, P2 1 2 1 2 1 , P2 1 , Pbca, C2/c, and Pna2 1 ) on the basis of statistical data [12][13][14][15][16][17]. This provides us with the possibility to confine the global search to the most frequent groups only.…”

Section: Packing Structuresmentioning

confidence: 99%

Packing structures and periodic band calculations on DPO (2,5-dipicryl-1,3,4-oxadiazole)

Wang

Shi²,

Gong

et al. 2009

Journal of Hazardous Materials

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Theoretical study on the adduct of chlorine trifluoride oxide and boron trifluoride—molecular and crystal structures, vibrational spectrum, and thermodynamic properties

Wang

Gong

et al. 2011

Int J of Quantum Chemistry

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To search for the most stable form and understand the relationship between the structure and property of the adduct of chlorine trifluoride oxide and boron trifluoride, various isomeric structures were constructed and optimized with the first principle methods. The most stable structure of the adduct has an ionic form. The vibrational spectra were calculated and assigned, and used to compute the standard thermodynamic properties. Molecular mechanics method was employed to predict the possible crystal packing of the adduct, and density functional theory method was used to refine the crystal structure and to calculate the energy band. The obtained band gap (3.40 eV) shows that the crystal is insensitive and stable under closed environment as was found experimentally.

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New statistical data on the topology of homomolecular organic crystals

Cited by 35 publications

References 6 publications

Structural classes and space groups of organic homomolecular crystals: new statistical data

Structural classes and space groups of organic homomolecular crystals: new statistical data

Packing structures and periodic band calculations on DPO (2,5-dipicryl-1,3,4-oxadiazole)

Theoretical study on the adduct of chlorine trifluoride oxide and boron trifluoride—molecular and crystal structures, vibrational spectrum, and thermodynamic properties

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