Sodium peroxide

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Sodium peroxide
Sodium peroxide
Sodium-peroxide-3D-vdW.png
Sodium peroxide 2grams.jpg
Identifiers
CAS number1313-60-6 YesY
PubChem14803
EC number215-209-4
UN number1504
RTECS numberWD3450000
Jmol-3D imagesImage 1
Properties
Molecular formulaNa2O2
Molar mass77.98 g/mol
Appearanceyellow to white powder
Density2.805 g/cm3
Melting point460 °C (860 °F; 733 K) (decomposes)
Boiling point657 °C (1,215 °F; 930 K) (decomposes)
Solubility in waterreacts violently
Solubilitysoluble in acid
insoluble in alkali
reacts with ethanol
Structure
Crystal structurehexagonal
Thermochemistry
Specific
heat capacity
C
89.37 J/mol K
Std molar
entropy
So298
95 J·mol−1·K−1[1]
Std enthalpy of
formation
ΔfHo298
−515 kJ·mol−1[1]
Gibbs free energy ΔG-446.9 kJ/mol
Hazards
MSDSExternal MSDS
EU Index011-003-00-1
EU classificationOxidizing Agent O Corrosive C
R-phrasesR8, R35
S-phrases(S1/2), S8, S27, S39, S45
NFPA 704
Flash pointNon-flammable
Related compounds
Other cationsLithium peroxide
Potassium peroxide
Rubidium peroxide
Caesium peroxide
Related sodium oxidesSodium oxide
Sodium superoxide
Related compoundsSodium hydroxide
Hydrogen peroxide
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 YesY (verify) (what is: YesY/N?)
Infobox references
 
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Sodium peroxide
Sodium peroxide
Sodium-peroxide-3D-vdW.png
Sodium peroxide 2grams.jpg
Identifiers
CAS number1313-60-6 YesY
PubChem14803
EC number215-209-4
UN number1504
RTECS numberWD3450000
Jmol-3D imagesImage 1
Properties
Molecular formulaNa2O2
Molar mass77.98 g/mol
Appearanceyellow to white powder
Density2.805 g/cm3
Melting point460 °C (860 °F; 733 K) (decomposes)
Boiling point657 °C (1,215 °F; 930 K) (decomposes)
Solubility in waterreacts violently
Solubilitysoluble in acid
insoluble in alkali
reacts with ethanol
Structure
Crystal structurehexagonal
Thermochemistry
Specific
heat capacity
C
89.37 J/mol K
Std molar
entropy
So298
95 J·mol−1·K−1[1]
Std enthalpy of
formation
ΔfHo298
−515 kJ·mol−1[1]
Gibbs free energy ΔG-446.9 kJ/mol
Hazards
MSDSExternal MSDS
EU Index011-003-00-1
EU classificationOxidizing Agent O Corrosive C
R-phrasesR8, R35
S-phrases(S1/2), S8, S27, S39, S45
NFPA 704
Flash pointNon-flammable
Related compounds
Other cationsLithium peroxide
Potassium peroxide
Rubidium peroxide
Caesium peroxide
Related sodium oxidesSodium oxide
Sodium superoxide
Related compoundsSodium hydroxide
Hydrogen peroxide
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 YesY (verify) (what is: YesY/N?)
Infobox references

Sodium peroxide is the inorganic compound with the formula Na2O2. This yellowish solid is the product of sodium ignited in oxygen.[2] It is a strong base. It exists in several hydrates and peroxyhydrates including Na2O2·2H2O2·4H2O, Na2O2·2H2O, Na2O2·2H2O2, and Na2O2·8H2O.[3]

Properties[edit]

Sodium peroxide crystallizes with hexagonal symmetry.[4] Upon heating, the hexagonal form undergoes a transition into a phase of unknown symmetry at 512 °C.[5] With further heating above the 675 °C melting point, the compound decomposes to Na2O, releasing O2, before reaching a boiling point.[6]

2 Na2O2 → 2 Na2O + O2

On contact with water sodium peroxide is hydrolyzed to give sodium hydroxide and hydrogen peroxide according to the reaction:

Na2O2 + 2 H2O → 2 NaOH + H2O2

Preparation[edit]

Sodium peroxide can be prepared on a large scale by the reaction of metallic sodium with oxygen at 130–200 °C, a process that generates sodium oxide, which in a separate stage absorbs oxygen:[5]

4 Na + O2 → 2 Na2O
2 Na2O + O2 → 2 Na2O2

This synthesis is no longer of commercial significance since more efficient routes to hydrogen peroxide have been found.[3] 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[edit]

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[5] and Flocool.[6] 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[edit]

  1. ^ a b Zumdahl, Steven S. (2009). Chemical Principles 6th Ed. Houghton Mifflin Company. p. A23. ISBN 0-618-94690-X. 
  2. ^ Greenwood, Norman N.; Earnshaw, Alan (1984). Chemistry of the Elements. Oxford: Pergamon Press. p. 98. ISBN 0-08-022057-6. 
  3. ^ 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
  4. ^ 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. 
  5. ^ a b c Macintyre, J. E., ed. Dictionary of Inorganic Compounds, Chapman & Hall: 1992.
  6. ^ a b Lewis, R. J. Sax's Dangerous Properties of Industrial Materials, 10th ed., John Wiley & Sons, Inc.: 2000.

External links[edit]