A metastable intermolecular composite (MIC)and methods for forming the same includes a first material and a second ma terial having an interfacial region therebetween. The first and second material are capable of an exothermic chemical reaction with one another to form at least one product and are in sufficiently close physical proximity to one another so that upon initiation the exothermic reaction develops into a self initiating reaction. At least one of said first and second materials include a metal that is reactive with water vapor at room temperature. The interfacial region averagesthick, such asembodiment, the first material is Al and the second material is CuOx
