Volume 1 Chapter 1 The CSD
The following graphs show the growth in the contents of the database.
The first graph shows the increase in the number of new entries input to the CSD by publication year from 1965 to 1990.
The second graph shows the increase in the average number of atoms in a structure for each publication year from 1965 to 1990.
The best picture of the increasing size of the CSD is given in the final graph by plotting the number of megabytes of information stored in the master archive for a given publication year. It shows, for example, that the amount of information processed for 1990 entries was approximately equal to the total for the period 1965-1977, and almost double that for 1984.
It can be seen that the CSD is a growing entity, hence the graphs above and the statistics presented below can only reflect its content at a single point in time, October 1992. However, with over 100,000 structures reported over a period of some 60 years, it is unlikely that gross changes in relative statistics will occur overnight! Hence, the information in this section provides a general overview of the growth of small-molecule crystallography, the types of compounds that have been studied, and a variety of other global facts concerning the CSD itself.
Overall Statistics
Number of entries 102589 Number of compounds 91325 Number of entries with 3D-coordinates 90315 Number of error-free 3D coordinate sets 88565 Number of entries with errors corrected by CCDC 11520 Number of atoms with 3D coordinates 4737722 Number of X-ray studies 101803 Number of neutron studies 786 Absolute configuration by X-ray methods 2635 Low temperature studies 10795 Number of different literature sources 634 Number of entries with perfect connectivity matching 76537 Number of entries with partial connectivity matching 8793 Number of entries with no connectivity matching 2990 Number of entries for which matching is impossible 14269
Chemical Class Statistics
Classes Types of Compounds Number of Entries % 1 - 12 Simple aliphatics 5471 5.3 13 - 23 Monocyclic hydrocarbons 5223 5.1 24 - 31 Polycyclic hydrocarbons 4337 4.2 32 - 42 Heterocyclic compounds 16543 16.1 43 - 59 Natural products 12356 12.0 60 - 61 Molecular complexes,clathrates 2811 2.7 62 - 70 Main group compounds 11837 11.5 71 - 75 Transition metal complexes (sigma,pi) 17603 17.2 76 - 86 Transition metal complexes (coordination) 26408 25.7
Precision of Structural Results
R Precision Number of Entries % 1 - 3 Exceptional 6778 6.6 3 - 4 Very high 16976 16.5 4 - 5 High 21225 20. 5 - 7 Good 29400 28.7 7 - 9 Average 13422 13.1 9 - 10 Fair 3564 3.5 10 - 15 Poor 6482 6.3 15 and over Bad 1656 1.6 Not reported ? 3086 3.0
Thus some 72% of the entries in the CSD would be judged as of good precision or better (R < 7%). A further 17% (making a total of 89% with R < 10%) would be judged as adequate for most molecular modelling applications.
Back to Table of Contents 