Figure 2

AdNDP natural bond orbital energy levels and bonding patterns of the ground states (GSs/GSs′) and transition states (TSs) of (a) C₁₀H₁₀ and (b) C₈BH₉ at PBE0/6-311 + G (d) level, with the two fluxional π-bonds and one fluxional σ-bond interlinked by arrowed lines from GS, TS, to GS′.