Electron Interaction in Hydrocarbon Multiple Ions

The relative ground-state electronic energies of singly and doubly-charged negative ions of unsaturated hydrocarbons are discussed in terms of systematically-approximated self-consistent molecular orbital theory. It is concluded that in the gas phase and in solution, R— ions will be stable by several ev to disproportionation into R and R=, which accords well with the recent paramagnetic resonance measurements of Lipkin et al. Further implications relevant to the solution chemistry of these ions are briefly discussed.