Patterson search - an alternative to direct methods

On the basis of the solution of six unknown structures by a real-space Patterson search the merits and limitations of the method are discussed. It is shown how chemical information can be used to provide a reliable starting point for direct methods when there is no automatic solution. Two examples demonstrate the potential usefulness of forcefield calculations for generating the geometries of appropriate search fragments in the absence of related crystal structures. The further discussion deals with future applications of the vector search method to determine large structures. A Patterson search program, which incorporates all necessary features of a modern program and is compatible with SHELX84, is being developed.