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 the University of Utah will use this award from the Chemistry Shared Instrumentation Program to help acquire an X-ray diffractometer. The new instrumentation will be used to enhance the following areas of chemical research: 1) Metal-pentadienyl chemistry 2) Mechanistic physical organic chemistry 3) Transition metal complexes 4) Ring conformation saturated six-membered rings containing phosphorus 5) Structural, conformational and stereochemical properties of organometallic compounds.