Sodium peroxide
{{Chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 455354975
| Name = Sodium peroxide
| ImageFile = Sodium-peroxide-unit-cell-3D-balls.png
| ImageName = Sodium peroxide
| ImageFile1 = Sodium-peroxide-3D-vdW.png
| ImageFile2 = Sodium peroxide 2grams.jpg
| IUPACName = Sodium peroxide
| OtherNames = Flocool
Solozone
Disodium peroxide
| Section1 = {{Chembox Identifiers
| CASNo = 1313-60-6
| CASNo_Ref = {{cascite|correct|CAS}}
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = 3GSN3JCJ5K
| PubChem = 14803
| RTECS = WD3450000
| EINECS = 215-209-4
| UNNumber = 1504
| SMILES = [O-][O-].[Na+].[Na+]
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 14119
| StdInChI_Ref = {{stdinchicite|changed|chemspider}}
| StdInChI = 1S/2Na.O2/c;;1-2/q2*+1;-2
| StdInChIKey_Ref = {{stdinchicite|changed|chemspider}}
| StdInChIKey = PFUVRDFDKPNGAV-UHFFFAOYSA-N
}}
| Section2 = {{Chembox Properties
| Formula = Na2O2
| MolarMass = 77.98 g/mol
| Appearance = yellow to white powder
| Density = 2.805 g/cm3
| Solubility = Reacts
| SolubleOther = Soluble in acid
Insoluble in base
Reacts with ethanol
| MeltingPtC = 460
| MeltingPt_notes = (decomposes)
| BoilingPtC = 657
| BoilingPt_notes = (decomposes)
| MagSus = −28.10·10−6 cm3/mol
}}
| Section3 = {{Chembox Structure
| CrystalStruct = hexagonal
}}
| Section4 = {{Chembox Thermochemistry
| DeltaHf = −515 kJ·mol−1{{cite book| author = Zumdahl, Steven S.|title =Chemical Principles 6th Ed.| publisher = Houghton Mifflin Company| year = 2009| isbn = 978-0-618-94690-7|page=A23}}
| DeltaGf = −446.9 kJ/mol
| HeatCapacity = 89.37 J/(mol·K)
}}
| Section7 = {{Chembox Hazards
| MainHazards = Caustic, reacts with water and ethanol, oxidizer
| ExternalSDS = [http://hazard.com/msds/mf/baker/baker/files/s4710.htm External MSDS]
| GHSPictograms = {{GHS03}}{{GHS05}}
| GHSSignalWord = Danger
| HPhrases = {{H-phrases|271|314}}
| PPhrases = {{P-phrases|210|220|221|260|264|280|283|301+330+331|303+361+353|304+340|305+351+338|306+360|310|321|363|370+378|371+380+375|405|501}}
| NFPA-H = 3
| NFPA-F = 0
| NFPA-R = 2
| NFPA-S = WOX
| FlashPt = Non-flammable
| Section8 = {{Chembox Related
| OtherAnions =
| OtherCations = Lithium peroxide
Potassium peroxide
Rubidium peroxide
Caesium peroxide
| OtherFunction = Sodium oxide
Sodium superoxide
Sodium ozonide
| OtherFunction_label = sodium oxides
| OtherCompounds = Sodium hydroxide
Hydrogen peroxide
}}
}}
Sodium peroxide is an inorganic compound with the formula Na2O2. This yellowish solid is the product of sodium ignited in excess oxygen.{{Greenwood&Earnshaw1st|page=98}} 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.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}}. The octahydrate, which is simple to prepare, is white, in contrast to the anhydrous material.
Properties
Sodium peroxide crystallizes with hexagonal symmetry.{{cite journal |author1=Tallman, R. L. |author2=Margrave, J. L. |author3=Bailey, S. W. | journal = J. Am. Chem. Soc. | title = The Crystal Structure Of Sodium Peroxide | year = 1957 | volume = 79 | pages = 2979–80 | doi = 10.1021/ja01568a087 | issue = 11|bibcode=1957JAChS..79.2979T }} Upon heating, the hexagonal form undergoes a transition into a phase of unknown symmetry at 512 °C. With further heating above the 657 °C boiling point, the compound decomposes to Na2O, releasing O2.Lewis, R. J. Sax's Dangerous Properties of Industrial Materials, 10th ed., John Wiley & Sons, Inc.: 2000.
: 2 Na2O2 → 2 Na2O + O2
Preparation
Commercially, sodium peroxide is produced from the elements in a two-stage process. First sodium is oxidized to sodium oxide:Macintyre, J. E., ed. Dictionary of Inorganic Compounds, Chapman & Hall: 1992.E. Dönges "Lithium and Sodium Peroxides" in Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. Vol. 1. p. 979.
:{{chem2|4Na + O2 -> 2 Na2O}}
Subsequently, this oxide is treated with more oxygen:
:{{chem2|2 Na2O + O2 -> 2 Na2O2}}
This was the method by which the substance was discovered in 1810 by Joseph Louis Gay-Lussac and Louis Jacques Thénard, as well as how it was for the first time commercially made by Hamilton Castner in the 1890s.{{Cite book |url=https://books.google.com/books?id=SoJNAAAAMAAJ&pg=PA356 |title=Bulletin of Pharmacy |date=1895 |language=en}}
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 can be sublimed by mild heating. The platinum or palladium catalyzes the reaction and is not attacked by the sodium peroxide.
The octahydrate can be produced by treating sodium hydroxide with hydrogen peroxide.{{cite book|title=Potassium Sodium Peroxide 8-Hydrate|author=R. A. Penneman |journal=Inorg. Synth.|volume=3|pages=1–4|year=1950|doi=10.1002/9780470132340.ch1}}
Uses
Sodium peroxide hydrolyzes to give sodium hydroxide and hydrogen peroxide according to the reaction
: Na2O2 + 2 H2O → 2 NaOH + H2O2
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.Lewis, R. J. Sax's Dangerous Properties of Industrial Materials, 10th ed., John Wiley & Sons, Inc.: 2000. 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:
: Na2O2 + CO2 → Na2CO3 + {{frac|1|2}} O2
: Na2O2 + H2O + 2 CO2 → 2 NaHCO3 + {{frac|1|2}} 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.
References
{{reflist}}
External links
- [http://www.inchem.org/documents/icsc/icsc/eics1606.htm International Chemical Safety Card 1606]
{{Sodium compounds}}
{{oxygen compounds}}