Sodium peroxide

Sodium peroxide
Other names

Sodium dioxide
Flocool
Solozone
Disodium peroxide
Identifiers
CAS number 1313-60-6 Y
PubChem 14803
EC number 215-209-4
UN number 1504
RTECS number WD3450000
Properties
Molecular formula Na2O2
Molar mass 77.98 g/mol
Appearance yellow to white powder
Density 2.805 g/cm3
Melting point

675 °C
Boiling point

decomp.
Solubility in water reacts violently
Structure
Crystal structure Hexagonal
Thermochemistry
Std enthalpy of
formation ΔfHo298		 −513 kJ/mol
Standard molar
entropy So298		 95 J K−1 mol−1
Hazards
MSDS External MSDS
EU Index 011-003-00-1
EU classification Oxidant (O)
Corrosive (C)
R-phrases R8, R35
S-phrases (S1/2), S8, S27, S39, S45
NFPA 704
0
2
1
OX
Flash point Non-flammable
Related compounds
Other cations Lithium peroxide
Potassium peroxide
Rubidium peroxide
Caesium peroxide
Related sodium oxides Sodium oxide
Sodium superoxide
Related compounds Sodium hydroxide
Hydrogen peroxide
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Sodium peroxide is the inorganic compound with the formula Na2O2. This solid is the product when sodium is burned with oxygen.[1] 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.[2]

Contents

Properties

Sodium peroxide crystallizes with hexagonal symmetry.[3] Upon heating, the hexagonal form undergoes a transition into a phase of unknown symmetry at 512 °C.[4] With further heating above the 675 °C melting point, the compound decomposes, releasing O2, before reaching a boiling point.[5]

Sodium peroxide is hydrolyzed to give sodium hydroxide and hydrogen peroxide 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.[2] 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, which in a separate stage absorbs oxygen:[4]

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. It may also be produced by passing ozone gas over solid sodium iodide inside a platinum or palladium tube. The ozone oxidizes the sodium to form sodium peroxide. The iodine 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[4] and Flocool.[5] 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 has similar uses.

References

  1. ^ Greenwood, Norman N.; Earnshaw, A. (1984). Chemistry of the Elements. Oxford: Pergamon. p. 98. ISBN 0-08-022057-6. 
  2. ^ a b Harald Jakob, Stefan Leininger, Thomas Lehmann, Sylvia Jacobi, Sven Gutewort “Peroxo Compounds, Inorganic” Ullmann's Encyclopedia of Industrial Chemistry, 2007, Wiley-VCH, Weinheim. doi:10.1002/14356007.a19_177.pub2
  3. ^ Tallman, R. L.; Margrave, J. L.; Bailey, S. W. (1957). "The Crystal Structure Of Sodium Peroxide". J. Am. Chem. Soc. 79 (11): 2979–80. doi:10.1021/ja01568a087. 
  4. ^ a b c Macintyre, J. E., ed. Dictionary of Inorganic Compounds, Chapman & Hall: 1992.
  5. ^ a b Lewis, R. J. Sax's Dangerous Properties of Industrial Materials, 10th ed., John Wiley & Sons, Inc.: 2000.

External links