This award from the Chemistry Research Instrumentation and Facilities (CRIF) Program and the Major Research Instrumentation (MRI) Program will enable the Departments of Chemistry and Biochemistry, Physics and Materials Engineering at The University of Maryland in College Park to acquire a CCD single crystal X-ray diffraction system, a powder X-ray diffraction system with variable temperature stage, and to upgrade an existing diffractometer. This equipment will enhance research in a number of areas including the following: (1) synthesis, structures and properties of solid state sulfides, selenides and oxysulfides, (2) insertion studies of transition metals into p-block polyanions, (3) studies of `colossal` magnetoresistance in doped rare-earth manganese perovskites, (4) studies of metal-thiometalate cooperativity in the transport of hazardous metals in anoxic ground waters, (5) self-assembled ionophores, and (6) organometallic chemistry and synthetic methods. 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.