The technique of X-ray crystallography is a powerful tool for the determination of the molecular structure of compounds as diverse as small polypeptides and complex metal clusters. When combined with the latest computer software, the technique is becoming remarkably easy to put into practice. The acquisition of X-ray crystallographic instrumentation markedly improves the ability of chemists to carry out frontier research. The Department of Chemistry at New York University will purchase an X-ray Diffractometer with support from the Chemistry Shared Instrumentation Program. The instrumentation will be used to enhance research in the following areas of chemistry: 1) Synthesis of natural products; computer assisted design of new biologically active molecules 2) Application of organometallic reagents in synthesis and catalysis; modeling of heterogeneous processes 3) Molecular characterization of the receptor sites of pharmacologically important molecules 4) Modeling of the active site of metalloenzymes; synthesis of novel cluster compounds containing sulfur and carbonyl ligands