Various aspects of Del Re's method, its extension and correlation with important properties such as nuclear quadrupole coupling constants and spin‐spin coupling constants are discussed. The Del Re parameters for the C–I bond have been evaluated and those for the C–F bond modified. The bond energies and the heats of formation for several σ‐systems have been calculated; the energies of a “bond‐orbital” for several alkanes have been found to be related with their ionization potentials. Copyright © 1972 John Wiley & Sons, Inc.