Sodium peroxide
Sodium peroxide: a strong base and oxidizing agent used in oxygen generation and mineral extraction.
Sodium peroxide is an inorganic compound with the formula Na2O2. It is the product of sodium ignited in excess oxygen. The pure substance is a white solid, but commercial and laboratory samples often appear as a yellowish solid due to sodium superoxide impurities. It is a strong base. This metal peroxide exists in several hydrates and peroxyhydrates including Na2O2·2H2O2·4H2O, Na2O2·2H2O, Na2O2·2H2O2, and Na2O2·8H2O. The octahydrate, which is simple to prepare, is white, like the pure anhydrous material.
- formula
- Na2O2
- discovered
- 1810
- discoverers
- Joseph Louis Gay-Lussac and Louis Jacques Thénard
- commercial_producer
- Hamilton Castner (1890s)
- appearance
- White solid (pure); yellowish (commercial due to impurities)
- key_property
- Strong base; decomposes to Na2O and O2 above 657 °C
Lore & Background
Sodium peroxide crystallizes with hexagonal symmetry. Upon heating, the hexagonal form undergoes a transition into a phase of unknown symmetry at 512 °C. With further heating above 657 °C, the compound decomposes to Na2O, releasing O2. The decomposition reaction is: 2 Na2O2 → 2 Na2O + O2. The discovery date is unclear from the source; the source states the substance was discovered in 1810 by Joseph Louis Gay-Lussac and Louis Jacques Thénard, but this date is disputed. Commercially, sodium peroxide is produced from the elements in a two-stage process: first sodium is oxidized to sodium oxide, then this oxide is treated with more oxygen. This was the method by which the substance was discovered, as well as how it was first commercially made by Hamilton Castner in the 1890s. The octahydrate can be produced by treating sodium hydroxide with hydrogen peroxide.
Reader's Guide
Sodium peroxide hydrolyzes to give sodium hydroxide and hydrogen peroxide: Na2O2 + 2 H2O → 2 NaOH + H2O2. It 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, it 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: Na2O2 + CO2 → Na2CO3 + O2, and Na2O2 + H2O + 2 CO2 → 2 NaHCO3 + O2. It is thus particularly useful in scuba gear, submarines, etc. Lithium peroxide and potassium superoxide have similar uses. Sodium peroxide was once used on a large scale for the production of sodium perborate, but alternative routes to that cleaning agent have been developed.
Did You Know?
- Sodium peroxide is a strong base.
- The octahydrate of sodium peroxide is white, like the pure anhydrous material.
- Sodium peroxide decomposes to sodium oxide and oxygen upon heating above 657 °C, without boiling.
- Sodium peroxide was first commercially made by Hamilton Castner in the 1890s.
More in Sodium Compounds 1-24
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