Barium peroxide

Barium peroxide is the chemical compound with the formula BaO2. This grey-white solid is one of the most common inorganic peroxides. Barium peroxide is an oxidizing agent, which is used for bleaching. It is used in fireworks as an oxidizer, which also gives a vivid green colour, as do all barium compounds.

Barium peroxide is a peroxide, containing O22 &minus; subunits wherein the oxygen atoms bond to each other as well as to the barium. The solid adopts the same structure as calcium carbide, CaC2.

Barium peroxide arises by the reversible absorption of O2 by barium oxide. The oxygen is released above 700°C.
 * BaO +  1/2 O2  BaO2

This reaction is the basis for the now-obsolete Brin Process for separating oxygen from the atmosphere. Other oxides, e.g. Na2O, behave similarly.

Hydrogen peroxide can also be prepared via the related reaction:
 * BaO2 + H2SO4 → H2O2 + BaSO4