the univalent anion O2-; "much of the O2 supporting cellular respiration is reduced to the superoxide anion O2-"

One of several toxic forms of oxygen, referred to collectively as free radicals.

superoxide ion. A binary compound containing oxygen in the -½ oxidation state. For example, KO2 is potassium superoxide, an ionic compound containing the superoxide ion, O2-.

A free radical created by aggregating platelets.

a free radical produced by oxygen metabolism consisting of an oxygen atom with an extra electron. It is reduced primarily by the enzyme SOD.

Superoxide is the anion O2−.Sawyer, D. T. Superoxide Chemistry, McGraw-Hill, With one unpaired electron, the superoxide ion is a free radical and therefore paramagnetic.