The technique of X-ray crystallography is a powerful tool for the determination of the molecular structure of compounds as diverse as small polypeptides 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. The Department of Chemistry at Keene State College will use this RUI award from the Chemistry Shared Instrumentation Program to help acquire an X-ray diffractometer. The instrument will be used to enhance research in the Department and in the Departments of neighboring institutions and to improve the undergraduate chemistry curriculum at Keene State. Among the areas of research to be enhanced by the aquisition are: 1) Structural investigations of copper (I)-laser dye clusters 2) Structure studies and molecular modeling of retinyl Schiff base-urethane elastomer systems 3) Transition metal complexes containing perfluorinated organic ligands 4) Cages, heterocycles and oligomers from coordinated phosphines 5) Chiral transition metal-olefin complexes: application to organic synthesis 6) New molybdenum (II) allyl compounds 7) Model compounds of liquid crystal polymer systems 8) Structural and conformational studies of ?n!(9,10) anthra- cenophanes 9) Transition metal complexes of tetraaza macrocyclic ligands.