The technique of X-ray crystallography is a powerful tool for the determination of the molecular structure of compounds as diverse as small peptides 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. With the aid of awards from the Chemistry Shared Instrumentation Program and NIH, the Department of Chemistry at the University of Texas at Austin will purchase an automatic diffractometer and the appropriate peripheral accessories to establish an X-ray diffractometry facility. The areas of chemistry that will be enhanced by the acquisition of the instrumentation include: 1) Cation Radical Pericyclic Reactions in Solution 2) Mechanisms of the Photochemistry and Electrochemistry of Ions, Radicals, and Radical Ions 3) Development of a Biomimetic Approach to Trichothecenes 4) Organometallic Structures of Biological Importance 5) Determination of the Structure of Covalently Bound Drug-DNA Adducts 6) Ligand-based Systematic Modification of Properties of Transition Metals 7) Synthesis and Properties of Chromium Complexes 8) Relationship between Structure and Function of Bioactive Natural Products 9) Study of Reactive Intermediates Generated by Photolysis or Thermolysis 10) The Synthesis of Novel Macrocyclic Compounds 11) Synthesis of Natural Products 12) Synthetic and Bioorganic Chemistry