Chemical Bonds without Bonding Electron Density — Does the Difference Electron‐Density Analysis Suffice for a Description of the Chemical Bond?

Formation of a covalent bond is not necessarily associated with an increase in electron density in the bonding region. This can be established by analysis of the single electron density distributions ρ( r ) with the aid of the assigned Laplace field ▽ 2 ρ( r ). For “bonds without bonding electron density ρ( r )”, it is decisive that the density ρ( r ) actually present in the region between the atoms results in a decrease in the local energy density and, hence, produces a stabilizing effect.