Chemistry and Complementarity

Abstract

The molecular view haunted chemists for a long time. Since this vision promised an outline of chemical reality in terms of basic building blocks, complementary approaches were neglected. Nowadays, the molecular program of chemistry has arrived at its successful termination so that the theoreticians find themselves challenged by new ways of looking at familiar facts of chemistry.
Our modern theoretical first principles allow a precise mathematical definition of Bohr’s notion of complementarity and enforce a pluralism in looking at the nature of things. In particular, complementarity is revealed with conspicious clarity everywhere in chemistry. The complementary aspects of classical and quantal descriptions of molecules and the complementarity between molecules and chemical substances are discussed. The discourse is concluded with a hint of how chemistry could help in learning complementary ways of thinking and to place complementarity into a wider perspective.