
An automatic procedure for crystal structure solution and refinement has been devised. It is able to take decisions at each critical point of the analysis by taking careful account of all information available at that point. The procedure has been implemented into the package UNIQUE (CRYSTALS+SIR88) and has been applied successfully to a wide variety of crystal structures. In most cases, the complete structure is recovered and refined without any user intervention. R values usually lie in the range 0.08-0.15.