Peroxide

Peroxide is an ion. Its chemical formula is O22-. Peroxide can be a reducing agent or an oxidizing agent. More often it is an oxidizing agent. It can be reduced to oxide or oxidized to oxygen. Hydrogen peroxide is the most common peroxide. Barium peroxide is another peroxide.
There are organic peroxides. These are chemical compounds where peroxide is attached to an organic molecule. Some of them are explosives.