A Brief Comment on the Development of the Theory of the Chemical Bond

Abstract

It is admirable that, as early as in the nineteenth century, chemists succeeded in defining concepts of the structure of substances that are in remarkable agreement with modern knowledge of the quantum theory of the chemical bond and with direct structural determinations using electron or neutron diffraction and X-ray analysis. Only in the theory published in 1916 by Kossel and Lewis did electrons assume a decisive role in concepts of the origin of the chemical bond. (The electron was discovered by Thomson only 19 years earlier, and 5 years earlier Rutherford proposed the planetary model of the atom.) The basic concepts of this very successful and innovative theory are based on the ideas of electrovalency and covalency, which are still accepted at the present time. This theory of the chemical bond forms a basis for the theory of mesomeric and inductive effects which contributed considerably to the rationalization of organic and inorganic chemistry (Robinson, Ingold, Arndt, Eistert). The work carried out by their predecessors (Kekulé, Cooper, Butlerov, Werner, and in spatial structure Le Bel and van’t Hoff) is of essential importance.