What is the correct decreasing order of thermodynamic stability for the molecular oxygen series? — Chemical Bonding Chemistry Question

💡 Solution & Explanation

Stability $\propto$ Bond Order. BO values: $O_2^+$ (15 $e^-$, BO=2.5), $O_2$ (16 $e^-$, BO=2.0), $O_2^-$ (17 $e^-$, BO=1.5), $O_2^{2-}$ (18 $e^-$, BO=1.0). Since adding electrons to $O_2$ fills antibonding orbitals, stability decreases: $O_2^+ > O_2 > O_2^- > O_2^{2-}$.