Definition for Superoxide
From Biology Forums Dictionary
A superoxide, also known by the obsolete name hyperoxide, is a compound that contains the superoxide anion with the chemical formula O2−. The systematic name of the anion is dioxide(1−). Superoxide anion is particularly important as the product of the one-electron reduction of dioxygen O2, which occurs widely in nature. Whereas molecular oxygen (dioxygen) is a diradical containing two unpaired electrons, the addition of a second electron fills one of its two degenerate molecular orbitals leaving a charged ionic species with single unpaired electron and a net negative charge of −1. Both dioxygen and superoxide ion are free radicals that exhibit paramagnetism.