The Natural Bond Orbital Lewis Structure Concept for Molecules, Radicals, and Radical Ions

Abstract

As the “Coulomb explosion”1 and other techniques add to our knowledge of molecular geometry, it is appropriate to recall the debt of gratitude that many theoretical concepts owe to structural studies. Indeed, new structural data have often provided the principal stimulus for new chemical concepts. Even prior to the discovery of the electron in the last century, qualitative structural inferences based on stoichiometry, number of isomers, and other lines of indirect chemical evidence were giving rise to models of molecular connectivity and geometry (e.g., the tetrahedral carbon atom of van’t Hoff and Le Bel2) that underlie current electronic theories of valence.