The recent synthesis of new compounds containing transition metals, such as iron or cobalt, and so-called "main group" elements, such as boron or arsenic, has provided examples of new types of chemical bonding to challenge the theorist. These new compounds also show great promise for practical application as precursors of solid state materials with desirable properties. For example, one of the compounds synthesized in the Principal Investigator's laboratory is a logical precursor for the preparation of metallic glass films. It is proposed to: a. prepare and charactierize metal-rich borane systems (including borides) and investigate their properties and reactivities; b. develop a fundamental understanding of metal-substituted borane, particularly the effect of the transition metal on the reactivity of a BH bond; c. design and execute the synthesis of selected borane mimics of known organometallic compounds; d. continue to develop the use of Lewis base adducts of borane and other main group hydrides as dual reagents, i.e., reagents that "activate" a transition metal compound and "insert" borane.