Chem-X and CAMBRIDGE. Comparison of computer generated chemical structures with X-ray crystallographic data

The structures of a number of molecules as determined by X-ray crystallography have been compared with the structures for the same molecules as calculated by the 3D structure generation program, Chem-X. In the group of molecules examined, ChemModel produced structures that were essentially identical to those based upon X-ray data in 57% of the cases. The corresponding figure for the widely used alternative model builder, CONCORD, was 38%. The superior performance of ChemModel was due entirely to that program's ability to generate multiple structures covering the entire conformational space.