Lithium peroxide

From Wikipedia, the free encyclopedia
Lithium peroxide
Lithium peroxide.svg
Li2O2.png
__ Li+     __ O−
Names
Other names
Dilithium peroxide, Lithium (I) peroxide
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.031.585 Edit this at Wikidata
UNII
  • InChI=1S/2Li.O2/c;;1-2/q2*+1;-2 checkY
    Key: HPGPEWYJWRWDTP-UHFFFAOYSA-N checkY
  • InChI=1/2Li.O2/c;;1-2/q2*+1;-2
    Key: HPGPEWYJWRWDTP-UHFFFAOYAV
  • [Li+].[Li+].[O-][O-]
Properties
Li2O2
Molar mass 45.881 g/mol
Appearance fine, white powder
Odor odorless
Density 2.31 g/cm3[1][2]
Melting point Decomposes to Li2O at ~340°C [3]
Boiling point NA
soluble
Solubility insoluble in alcohol
Structure
hexagonal
Thermochemistry
Std enthalpy of
formation (ΔfH⦵298)
 -13.82 kJ/g
Hazards
GHS labelling:
GHS03: OxidizingGHS05: Corrosive
Signal word
 Danger
H271, H272, H314
P210, P220, P221, P260, P264, P280, P283, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P306+P360, P310, P321, P363, P370+P378, P371+P380+P375, P405, P501
NFPA 704 (fire diamond)
3
0
2
OX
Related compounds
Other cations
 Sodium peroxide
Potassium peroxide

Caesium peroxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N  (what is checkY☒N ?)
Infobox references

Lithium peroxide is the inorganic compound with the formula Li2O2. It is a white, nonhygroscopic solid. Because of its high oxygen:mass and oxygen:volume ratios, the solid has been used to remove CO2 from the atmosphere in spacecraft.[4]

Preparation[]

It is prepared by the reaction of hydrogen peroxide and lithium hydroxide. This reaction initially produces lithium hydroperoxide:[4][5]

LiOH + H2O2 → LiOOH + H2O

This lithium hydroperoxide has also been described as lithium peroxide monoperoxohydrate trihydrate (Li2O2·H2O2·3H2O). Dehydration of this material gives the anhydrous peroxide salt:

2 LiOOH → Li2O2 + H2O2

Li2O2 decomposes at about 450 °C to give lithium oxide:

2 Li2O2 → 2 Li2O + O2

The structure of solid Li2O2 has been determined by X-ray crystallography and density functional theory. The solid features an eclipsed "ethane-like" Li6O2 subunits with an O-O distance of around 1.5 Å.[6]

Uses[]

It is used in air purifiers where weight is important, e.g., spacecraft to absorb carbon dioxide and release oxygen in the reaction:[4]

2 Li2O2 + 2 CO2 → 2 Li2CO3 + O2

It absorbs more CO2 than does the same weight of lithium hydroxide and offers the bonus of releasing oxygen.[7] Furthermore, unlike most other alkali metal peroxides, it is not hygroscopic.

The reversible lithium peroxide reaction is the basis for a prototype lithium–air battery. Using oxygen from the atmosphere allows the battery to eliminate storage of oxygen for its reaction, saving battery weight and size.[8]

The successful combination of a lithium-air battery overlain with an air-permeable mesh solar cell was announced by The Ohio State University in 2014.[9] The combination of two functions in one device (a "solar battery") is expected to reduce costs significantly compared to separate devices and controllers as are currently employed.

See also[]

References[]

  1. ^ "Physical Constants of Inorganic Compounds," in CRC Handbook of Chemistry and Physics, 91st Edition (Internet Version 2011), W. M. Haynes, ed., CRC Press/Taylor and Francis, Boca Raton, Florida. (pp: 4-72).
  2. ^ Speight, James G. (2005). Lange's Handbook of Chemistry (16th Edition). (pp: 1.40). McGraw-Hill. Online version available at: http://www.knovel.com/web/portal/browse/display?_EXT_KNOVEL_DISPLAY_bookid=1347&VerticalID=0
  3. ^ Phys.Chem.Chem.Phys.,2013,15, 11025. doi:10.1039/c3cp51056e
  4. ^ a b c Greenwood, Norman N.; Earnshaw, Alan (1984). Chemistry of the Elements. Oxford: Pergamon Press. p. 98. ISBN 978-0-08-022057-4.
  5. ^ 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.
  6. ^ L. G. Cota and P. de la Mora "On the structure of lithium peroxide, Li2O2" Acta Crystallogr. 2005, vol. B61, pages 133-136. doi:10.1107/S0108768105003629
  7. ^ Ulrich Wietelmann, Richard J. Bauer "Lithium and Lithium Compounds" in Ullmann's Encyclopedia of Industrial Chemistry 2005, Wiley-VCH: Weinheim. doi:10.1002/14356007.a15_393.pub2
  8. ^ Girishkumar, G.; B. McCloskey; AC Luntz; S. Swanson; W. Wilcke (July 2, 2010). "Lithium- air battery: Promise and challenges". The Journal of Physical Chemistry Letters. 1 (14): 2193–2203. doi:10.1021/jz1005384.
  9. ^ [1] Patent-pending device invented at The Ohio State University: the world’s first solar battery.

External links[]

Retrieved from ""