This project, in the Inorganic, Bioinorganic and Organometallic Chemistry Program, is concerned with the synthesis, and the physical and chemical characterization of polynuclear compounds that contain both transition elements (M) and heavy non-transition metal elements (E) as an integral part of the cluster framework. Synthetic strategies to be followed include 1) substitution of E-bound halide in existing cluster compounds, 2) homolytic bismuth-carbon bond cleavage in metallated bismuth compounds to reactive fragments for coupling reactions, 3) redox reactions on existing stable small clusters to generate reactive fragments that may couple to give larger fragments, 4) reactions of known Group 9 and 10 metal clusters with "bare" bismuth atoms generated by thermal decomposition of bismuth hydride, 5) the reactions of bismuth and antimony Zintl ions with transition metal compounds that have readily substituted ligands, and 6) cathodic dissolution of bismuth alloys in the presence of ligands to trap the anticipated small anionic clusters. It is increasingly clear that alloys and compounds that contain transition metals and non-metallic elements have interesting and potentially technologically important electronic and magnetic properties, and unique catalytic properties. However, the fundamental aspects of the bonding interactions between transition metals and heavy non-metallic elements has received little attention so that interpretation and prediction of properties are currently impossible. This project has as its primary objective the acquisition of information concerning interactions of such elements through the study of cluster compounds that contain bonds between transition metal atoms and non-metallic elements. Decomposition reactions of these clusters may also lead to new alloys with useful properties.