Superconductivity: Where Chemistry Meets Physics

While the occurrence of superconductivity is usually viewed as an instability of the conduction electrons in a metal, the continuing discovery of new classes of superconducting materials suggests the complementary view that superconductivity is also a statement about the chemistry of these new materials. The argument is made that these and future classes of interesting superconductors will reside where the useful description of the materials changes character: where bonds become bands, where local becomes delocal. How different classes of superconductors manifest this dichotomy in different ways will be discussed.