International
Tables for
Crystallography
Volume C
Mathematical, physical and chemical tables
Edited by E. Prince

© International Union of Crystallography 2006
International Tables for Crystallography (2006). Vol. C. ch. 9.5, p. 790

Section 9.5.2.1. Selection of crystallographic data

F. H. Allen,a D. G. Watson,a L. Brammer,b A. G. Orpenc and R. Taylora

a Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, England,bDepartment of Chemistry, University of Missouri–St Louis, 8001 Natural Bridge Road, St Louis, MO 63121-4499, USA, and cSchool of Chemistry, University of Bristol, Bristol BS8 1TS, England

9.5.2.1. Selection of crystallographic data

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All results given in Table 9.5.1.1[link] are based on X-ray and neutron diffraction results retrieved from the September 1985 version of the CSD. Neutron diffraction data only were used to derive mean bond lengths involving H atoms. This version of the CSD contained results for 49 854 single-crystal diffraction studies of organo-carbon compounds; 10 324 of these satisfied the acceptance criteria listed below and were used in the averaging procedures:

  • (i) Structure is `organic', i.e. belongs to the CSD chemical classes 1–65 or 70 (Cambridge Crystallographic Data Centre User Manual, 1978[link]).

  • (ii) Atomic coordinates for the structure have been published and are available in the CSD.

  • (iii) Structure was determined from diffractometer data.

  • (iv) Structure does not contain unresolved numeric data errors from the original publication (such errors are usually typographical and are normally resolved by consultation with the authors).

  • (v) Structure was not reported to be disordered.

  • (vi) Only structures of higher precision were included on the basis of either (a) the crystallographic R factor was [\le] 0.07 and the reported mean estimated standard deviation (e.s.d.) of the C—C bond lengths was [\le] 0.010 Å (corresponds to AS flag = 1 or 2 in the CSD), or (b) the crystallographic R factor [\le] 0.05 and the mean e.s.d. for C—C bonds was not available in the database (AS = 0 in the CSD).

  • (vii) Where the structure of a given compound had been determined more than once within the limits of (i)–(vi), then only the most precise determination was used.

References

First citation Cambridge Crystallographic Data Centre User Manual (1978). 2nd ed. Cambridge University, England.Google Scholar








































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