- a yellowish-white, hygroscopic, water-soluble powder, Na2O2, used chiefly as a bleaching agent and as an oxidizing agent.
- a yellowish-white odourless soluble powder formed when sodium reacts with an excess of oxygen: used as an oxidizing agent in chemical preparations, a bleaching agent, an antiseptic, and in removing carbon dioxide from air in submarines, etc. Formula: Na 2 O 2
