Lithium peroxide

Lithium peroxide
Other names Dilithium peroxide, Lithium (I) peroxide
Identifiers
CAS number	12031-80-0
PubChem	6093265
ChemSpider	23787 Y
Jmol-3D images	Image 1
SMILES [Li+].[Li+].[O-][O-]
InChI InChI=1S/2Li.O2/c;;1-2/q2*+1;-2 Y Key: HPGPEWYJWRWDTP-UHFFFAOYSA-N Y InChI=1/2Li.O2/c;;1-2/q2*+1;-2 Key: HPGPEWYJWRWDTP-UHFFFAOYAV
Properties
Molecular formula	Li2O2
Molar mass	45.881 g/mol
Appearance	fine odorless, white powder
Density	2.31 g/cm3
Melting point	195°C
Boiling point	Decomposes to Li2O
Solubility in water	soluble
Thermochemistry
Std enthalpy of formation ΔfHo298	-13.82 kJ/g
Hazards
EU classification	not listed
NFPA 704	0 3 2 OX
Y peroxide (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Lithium peroxide is the inorganic compound with the formula Li₂O₂. This solid was deployed to remove CO₂ from the atmosphere in the vehicles used in Apollo mission.

Preparation

It is prepared by the reaction of hydrogen peroxide and lithium hydroxide, which initially produces lithium hydroperoxide:^[1]

LiOH.H₂O + H₂O₂ → LiOOH.H₂O + H₂O

Dehydration of the hydroperoxide gives the peroxide:

2LiOOH.H₂O → Li₂O₂ + H₂O₂ + 2H₂O

It decomposes above 195 °C to give lithium oxide:

2Li₂O₂ → 2Li₂O + O₂

Uses

It is used in air purifiers where weight is important e.g. spacecraft to absorb carbon dioxide and release oxygen in the reaction^[1]:

2Li₂O₂ + 2CO₂ → 2Li₂CO₃ + O₂

It absorbs more CO₂ than does the same weight of lithium hydroxide and offers the bonus of releasing dioxygen.^[2]

See also

• Lithium oxide

References

1. ^ ^{a b} Greenwood, Norman N.; Earnshaw, A. (1984). Chemistry of the Elements. Oxford: Pergamon. p. 98. ISBN 0-08-022057-6. 
2. ^ Günter Petzow, Fritz Aldinger, Sigurd Jönsson, Peter Welge, Vera van Kampen, Thomas Mensing, Thomas Brüning"Beryllium and Beryllium Compounds" in Ullmann's Encyclopedia of Industrial Chemistry 2005, Wiley-VCH, Weinheim. doi:10.1002/14356007.a04_011.pub2

External links

• WebElements entry