NaO2

NaO2, or sodium superoxide, is an inorganic compound consisting of Na+ cations and the superoxide anion O2−. It is a white to pale crystalline solid that is paramagnetic because the O2− unit carries an unpaired electron. As a superoxide, NaO2 is a strong oxidizer and reacts readily with water and carbon dioxide.

Preparation and handling

Sodium superoxide can be prepared by direct reaction of sodium metal with molecular oxygen under controlled, non-aqueous conditions, often in processes linked to oxygen-generation materials. In practice, it is handled and stored in dry, inert environments to prevent hydrolysis or reaction with moisture. Because it reacts with water and CO2 from the air, it is typically kept sealed and away from humid atmospheres.

Reactions and properties

Upon contact with water, NaO2 hydrolyzes to form sodium hydroxide and oxygen, releasing heat in the process. Interaction with CO2 can lead to the formation of carbonate species, diminishing the material’s oxidizing capacity and altering its composition. In air or moisture, NaO2 gradually decomposes, and the presence of moisture accelerates these changes.

Applications

NaO2 has been explored for oxygen-generation purposes in closed environments, such as submarines or spacecraft, where oxidation reactions release oxygen gas. It is less common in practical use than potassium superoxide (KO2) but has been studied as a component of oxygen-supplying or scrubbing systems in specialized applications and research contexts.

Safety

As a strong oxidizer, NaO2 presents fire and explosion hazards, particularly in contact with organic materials or reducing agents. It is highly reactive with water and moisture, releasing oxygen and heat. Handling requires dry, inert conditions, appropriate protective equipment, and strict control of exposure to air and moisture.