Pauling “3-Electron Bonds”, 4-Electron 3-Centre Bonding, and the Need for an “Increased Valence” Theory

Abstract

In elementary chemical bonding theory, a rather neglected concept is a type of chemical bond that Pauling has designated as the “3-electron bond”. This type of bond is usually represented as A···B and it involves three electrons distributed amongst two overlapping atomic orbitals centred on the atoms A and B. Alternative designations are either “3-electron 2-centre” bond or “3-electron 2-orbital” bond.