In the Fig. the kinetic-exchange energy and the effective Coulomb interaction, both as a function of interatomic distance R, is compared for H 2 and H - 2 . From the bonding perspective, the plots provide an insight into the nature of bonding in those molecules. The H 2 molecule exhibits characteristics typical of covalent bonding, with the exchange interaction significantly higher than effective Coulomb interaction near the equilibrium distance (it is almost 4 times stronger). The effective kinetic energy decreases as the distance increases, still remaining larger than the effective potential en-ergy. For the H - 2 the exchange interaction energy decreases steadily with the increasing R with the J kex /E ef f ratio less than 1 around R eq . One should note that this relation does not relate to the ionic bonding character. 37.39 1.604