Hydroperoxyl radical ($\mathrm{H}{\mathrm{O}}_2$)

The hydroperoxyl radical is $\mathrm{H}{\mathrm{O}}_2\cdot$, a reactive hydrogen-oxygen species. It is related by proton transfer to the superoxide radical anion.

Its reactions help connect radical production, oxygen chemistry, and termination pathways in gases and solutions. Because its speciation depends on the medium, neutral hydroperoxyl and charged superoxide should not be treated as the same species under every condition.