Sodium peroxide is the inorganic compound

Inorganic compound

Inorganic compounds have traditionally been considered to be of inanimate, non-biological origin. In contrast, organic compounds have an explicit biological origin. However, over the past century, the classification of inorganic vs organic compounds has become less important to scientists,...

 with the formula Na₂O₂. This solid is the product when sodium is burned with oxygen. It is a strong base and a potent oxidizing agent. It exists in several hydrates and peroxyhydrates including Na₂O₂·2H₂O₂·4H₂O, Na₂O₂·2H₂O, Na₂O₂·2H₂O₂, and Na₂O₂·8H₂O.

Properties

Sodium peroxide crystallizes with hexagonal symmetry. Upon heating, the hexagonal form

Polymorphism (materials science)

Polymorphism in materials science is the ability of a solid material to exist in more than one form or crystal structure. Polymorphism can potentially be found in any crystalline material including polymers, minerals, and metals, and is related to allotropy, which refers to chemical elements...

 undergoes a transition into a phase of unknown symmetry at 512 °C. With further heating above the 675 °C melting point, the compound decomposes, releasing O₂, before reaching a boiling point.

Sodium peroxide is hydrolyzed

Hydrolysis

Hydrolysis is a chemical reaction during which molecules of water are split into hydrogen cations and hydroxide anions in the process of a chemical mechanism. It is the type of reaction that is used to break down certain polymers, especially those made by condensation polymerization...

 to give sodium hydroxide and hydrogen peroxide

Hydrogen peroxide

Hydrogen peroxide is the simplest peroxide and an oxidizer. Hydrogen peroxide is a clear liquid, slightly more viscous than water. In dilute solution, it appears colorless. With its oxidizing properties, hydrogen peroxide is often used as a bleach or cleaning agent...

 according to the reaction:

Na₂O₂ + 2 H₂O → 2 NaOH +H₂O₂

Preparation

The synthesis is no longer of commercial significance since the development of efficient routes to hydrogen peroxide. Sodium peroxide formerly was prepared on a large scale by the reaction with sodium with oxygen at 130–200 °C, a process that generates sodium oxide

Sodium oxide

Sodium oxide is a chemical compound with the formula Na2O. It is used in ceramics and glasses, though not in a raw form. Treatment with water affords sodium hydroxide....

, which in a separate stage absorbs oxygen:

4 Na + O₂ → 2 Na₂O

2 Na₂O + O₂ → 2 Na₂O₂

More specialized routes have been developed. At ambient temperatures (0–20 °C), O₂ reacts with a dilute (0.1–5.0 mole percent) sodium amalgam

Sodium amalgam

Sodium amalgam, commonly denoted Na, is an alloy of mercury and sodium. The term amalgam is used for alloys, intermetallic compounds, and solutions involving mercury as a major component. Sodium amalgam is often used in reactions as strong reducing agents with better handling properties compared...

. It may also be produced by passing ozone gas over solid sodium iodide

Sodium iodide

Sodium iodide is a white, crystalline salt with chemical formula NaI used in radiation detection, treatment of iodine deficiency, and as a reactant in the Finkelstein reaction.-Uses:Sodium iodide is commonly used to treat and prevent iodine deficiency....

 inside a platinum

Platinum

Platinum is a chemical element with the chemical symbol Pt and an atomic number of 78. Its name is derived from the Spanish term platina del Pinto, which is literally translated into "little silver of the Pinto River." It is a dense, malleable, ductile, precious, gray-white transition metal...

 or palladium

Palladium

Palladium is a chemical element with the chemical symbol Pd and an atomic number of 46. It is a rare and lustrous silvery-white metal discovered in 1803 by William Hyde Wollaston. He named it after the asteroid Pallas, which was itself named after the epithet of the Greek goddess Athena, acquired...

 tube. The ozone oxidizes the sodium to form sodium peroxide. The iodine

Iodine

Iodine is a chemical element with the symbol I and atomic number 53. The name is pronounced , , or . The name is from the , meaning violet or purple, due to the color of elemental iodine vapor....

 is freed into iodine crystals, which can be sublimed by mild heating. The platinum or palladium catalyzes the reaction and is not attacked by the sodium peroxide.

Uses

Sodium peroxide was used to bleach wood pulp for the production of paper and textiles. Presently it is mainly used for specialized laboratory operations, e.g. the extraction of minerals from various ores. Sodium peroxide may go by the commercial names of Solozone and Flocool. In chemistry preparations, sodium peroxide is used as an oxidizing agent. It is also used as an oxygen source by reacting it with carbon dioxide to produce oxygen and sodium carbonate; it is thus particularly useful in scuba gear, submarines, etc. Lithium peroxide

Lithium peroxide

Lithium peroxide is the inorganic compound with the formula Li2O2. This solid was deployed to remove CO2 from the atmosphere in the vehicles used in Apollo mission.-Preparation:...

has similar uses.

External links

• International Chemical Safety Card 1606