This research, part of the Experimental Physical Chemistry Program, utilizes calorimetric and nuclear magnetic resonance techniques to study Lewis acid-base interactions involving halides. It forms the basis for the understanding of inorganic and organic reactions, intermolecular interactions such as hydrogen bonding, and molecular orbital theory. The stoichiometry, equilibrium constants, enthalpy changes, and empirical measures of Lewis interactions will be determined for solution equilibria involving Group 14 and Group 15 Lewis acids. The multiple equilibria involved in tri- and tetrahalide derivatives will be explored by schematic mapping analysis of calorimetric and nuclear magnetic resonance data. The solvent dependence of equilibria for organotin mono and dihalides will be determined and correlated with solvent characteristics.