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How are oxide ions, peroxide ions, and superoxide ions different?

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A color-coded periodic table of the elements displays each element's symbol and atomic number, with categories such as alkali metals, noble gases, halogens, transition metals, and actinoid elements distinguished by different background colors. — oxygen group element Modern version of the periodic table of the elements (printable).

Oxide, peroxide, and superoxide ions are distinguished primarily by their charge and the presence of oxygen-oxygen covalent bonds. These ions represent different ways oxygen can accept electrons to achieve a stable electronic structure.12

Oxide ion ( $O^{2 -}$ ): This ion is created when oxygen atoms gain two electrons to fill their outer orbitals, resulting in a charge of $- 2$ . It is found in many ionic metal oxides, such as calcium oxide ( $C a O$ ).13
Peroxide ion ( $O_{2}^{2 -}$ ): This species contains two oxygen atoms linked by a single covalent bond, with an overall charge of $- 2$ . Each oxygen atom is effectively assigned an oxidation state of $- 1$ . Peroxides, such as barium peroxide ( $B a O_{2}$ ), are strong oxidizing agents and act as bases in water.341
Superoxide ion ( $O_{2}^{-}$ ): This ion also features an oxygen-oxygen covalent bond but carries a single negative charge ( $- 1$ ). In this state, oxygen has an oxidation number of $- 1 / 2$ . Metallic superoxides, such as potassium superoxide ( $K O_{2}$ ), are paramagnetic solids that react vigorously with water to produce oxygen gas.351

While oxide ions are common in many stable compounds, the stability of peroxides and superoxides is often influenced by the size and electropositive character of the associated metal cation.35