Sodium peroxide

Sodium peroxide is a sodium salt of hydrogen peroxide. Its formula is Na₂O₂. It is somewhat unstable and a strong oxidizer.

Properties

Physical

Sodium peroxide exists in two forms: anhydrous and octahydrate Na₂O₂*8H₂O.

Anhydrous sodium peroxide is a yellow powder. The octahydrate appears as colorless crystals with a low melting point (30 Celsius).

Chemical

Anhydrous sodium peroxide reacts with water. Part of it is hydrolyzed irreversibly into oxygen, sodium hydroxide and water. Part is converted into the hydrate, which undergoes reversible hydrolysis and can be crystallized out of the solution by adding ethanol. The octahydrate is soluble in water without decomposition.

It reacts with carbon dioxide to produce oxygen and sodium carbonate.

Attempts to calcine the octahydrate result in its decomposition, the crystals turn into sodium hydroxide. There is no easily available way to turn the octahydrate into the anhydrous salt.

Availability

Sodium peroxide, usually anhydrous, is commonly sold by various chemical suppliers.

Preparation

Anhydrous sodium peroxide is usually prepared by burning sodium metal in air. The octahydrate can be easily prepared by a simple neutralization reaction with hydrogen peroxide (a weak acid) and sodium hydroxide. The crystals can be displaced out of solution with ethanol.

Handling

Safety

Avoid contact of anhydrous hydrogen peroxide with organic solvents. This may result in fire or explosions.

Storage

Anhydrous sodium peroxide should be kept in a tightly closed jar, to avoid contact with water vapor. The octahydrate should be kept in a cold place.

Disposal

Any form of sodium peroxide can be neutralized by adding any acid and manganese dioxide. This reduces the component to a sodium salt of that acid and oxygen.