This award from the Chemistry Research Instrumentation Program will assist the Department of Chemistry at the University of Southern California in the purchase of an x-ray diffractometer with a rotating anode source and low temperature capability. Research areas to be supported by the acquisition of this instrument are: 1. X-ray diffraction studies of long lived carbocation salts. 2. Reactions of hydrocarbons in the coordination sphere of soluble metal complexes. 3. Structural coordination chemistry. 4. Structure analysis of metal hydrides and other compounds by x-ray and neutron diffraction. 5. Study of the relationships between structure, reactivity and energetics in organometallic complexes. 6. Synthetic organic, bioorganic and organometallic chemistry. %%% An x-ray diffractometer is an instrument used to measure the precise structure of a chemical compound, or molecule. Distances between the atoms in a molecule are measured to a precision of about 0.1 picometers (there are 1,000,000,000,000 picometers in one meter; one meter is about three feet). X-ray diffraction measurements also give precise information about the relative location and orientation of a given molecule to the other neighboring molecules in the single crystal.