# What is the difference between oxides , peroxides and superoxides ?

Oxides, oxidation state $- I I$; peroxides, oxidation state $- I$; superoxides, oxidation state $- \frac{1}{2}$.
These oxygen derivatives differ by oxidation number. Typical oxides are $N {a}_{2} O$, $F {e}_{2} {O}_{3}$, $B a O$; these feature the oxide anion, ${O}^{2 -}$.
Peroxides are derivatives of hydrogen peroxide, $H - O - O - H$, and feature an $O - O$ bond. The formal oxidation state of oxygen here is ${O}^{- I}$, i.e. the peroxide dianion is considered to be ""^(-)O-O^(-)
Superoxides have a formal oxidation state of $- \frac{1}{2}$, and are known as alkali metal salts, i.e. $M {O}_{2}$ $\left(M = K , N a , R b\right)$. They are a portable form of oxygen, and are used as oxygen supplies for firefighters.