This award from the Chemistry Research Instrumentation and Facilities Program will assist the Department of Chemistry at the University of Colorado--Boulder in the purchase of a modern single-crystal diffraction system. This new instrumentation will enhance greatly research in a number of areas, including the following: (1) transition metal complexes containing quinone and radical semiquinone ligands; (2) role of metal sulfides in carbon-heteroatom and metal sulfur bond cleavage; (3) intramolecular Lewis acids as stereochemical control elements; (4) 2,5-Dicarboxy-Stabilized 1,4-Dihydropyrazines as electron donors in the synthesis of organic conductors and magnets; (5) extended skeletally stabilized cyclic and linear phosphazanes; and (6) single crystal x-ray structures of molecular rods and connectors. 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 that molecule relative to the neighboring molecules.