# What are the oxidation states of oxygen?

$O : - I I , - I , 0 , + I , + I I$.
Obviously, the $- I I$ oxidation state is most common. In the $\text{peroxide}$ linkage, i.e. $R O - O R$, $H O - O H$, in which the $O - O$ is readily cleaved, the oxidation state is $- I$
Of course, oxygen gas is zerovalent (and in ozone, ""^(-)O-O^(+)=O, $- I , + I , 0$. In $O {F}_{2}$, clearly $O$ takes a $+ I I$ oxidation state. Why clearly?
In $F - O - O - F$ oxygen takes a $+ I$ oxidation state. That is truly something I would not want to handle (and they call it $\text{FOOF}$ for its reactivity!).