How does O2 perform homolytic fission when its a double covalently bonded molecule?
Two e- leave with one (neutral) oxygen atom, two leave with the other. It takes more energy to cleave the double bond and create an oxygen radical than a chlorine radical, and little oxygen isn’t so stable as large chlorine, because the charge density on the oxygen radical is greater, but there’s no reason at all to think that this can’t happen. Otherwise, there wouldn’t be an oxygen atom with 6 protons and an atomic weight of 16, there would be an oxygen atom with 12 protons and an atomic weight of 24 (because you’re basically proposing that O2 can’t be separated into 2 O). When molecular oxygen ::O=O:: binds an oxygen radical O::: it contributes a pair of electrons to form a sigma bond ::O=O:-O::: (better represented as a resonance [::O=O:-O::: <--> :::O-O:=O::]). There is no unpaired electron in ozone; perhaps the structure you’re looking at is incorrectly drawn.
