3 Molecular structure from X-ray diffraction

Abstract

Recent developments in the determination of molecular structures from X-ray diffraction data are discussed. While the problems associated with chemical crystallography using single crystals have largely been solved, those with structure from powders and of macromolecules are still the subjects of active research. New and improved methods in structure determination in both these fields dominated the crystallographic press in 2002. Developments that first appeared in protein crystallography are now finding application in powder methods e.g. the use of structure envelopes determined from low resolution data, or maximum likelihood techniques to extract unbiased information from data. Each of these areas of work is now yielding results routinely in a way that would have been unimaginable a decade ago.