This award from the Chemistry Research Instrumentation and Facilities Program will assist the Department of Chemistry at University of California at Berkeley in the purchase of a new X-ray diffractometer equipped with a high-resolution, high-sensitivity area detector with associated computers. This new instrumentation will enhance greatly research in a number of areas including the following: 1) Stereognostic Coordination Chemistry 2) Lanthanide and Actinide Coordination Chemistry 3) Coordination Chemistry of Biological Iron Transport 4) Metal Complexes with Te and Se-Containing Ligands 5) Transition Metal-Silicon Chemistry 6) Synthesis and Study of New Electroactive Polymers 7) Single-Source Precursors to Elaborate Solid-State Structures 8) Structures of the Oxide Superconductors and Related Materials and 9) Conformationally Constrained and Templated Peptides. The X-ray diffractometer is used to make accurate and precise measurements of the full three- dimensional structure of a molecule. The information obtained gives the precise values of all the bond distances and bond angles of a given molecule and it gives accurate information about the spatial arrangement of the molecule relative to the neighboring molecules.