Lithium oxide

Lithium oxide
IUPAC name Lithium oxide
Other names Lithium monoxide Lithia
Identifiers
CAS number	12057-24-8 Y
PubChem	166630
ChemSpider	145811 Y
RTECS number	OJ6360000
Jmol-3D images	Image 1
SMILES [Li+].[Li+].[O-2]
InChI InChI=1S/2Li.O/q2*+1;-2 Y Key: FUJCRWPEOMXPAD-UHFFFAOYSA-N Y
Properties
Molecular formula	Li2O
Molar mass	29.88 g/mol
Appearance	white solid
Density	2.013 g/cm3
Melting point	1570 °C, 1843 K, 2858 °F
Solubility in water	decomposes 6.67 g/100 mL (0 °C) 10.02 g/100 mL (100 °C)
log P	9.23
Refractive index (nD)	1.644 [1]
Structure
Crystal structure	Antifluorite (cubic), cF12
Space group	Fm3m, No. 225
Coordination geometry	Tetrahedral (Li+); cubic (O2–)
Thermochemistry
Std enthalpy of formation ΔfHo298	-20.01 kJ/g
Specific heat capacity, C	1.8105 J/g K
Hazards
EU Index	Not listed
Main hazards	Corrosive, reacts violently with water
Flash point	Non-flammable
Related compounds
Other anions	Lithium sulfide
Other cations	Sodium oxide Potassium oxide Rubidium oxide Caesium oxide
Related lithium oxides	Lithium peroxide Lithium superoxide
Related compounds	Lithium hydroxide
Y oxide (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 oxide (Li₂O) or lithia is an inorganic chemical compound. Lithium oxide is formed along with small amounts of lithium peroxide when lithium metal is burned in the air and combines with oxygen^[2]:

4Li+O₂ → 2Li₂O.

Pure Li₂O can be produced by the thermal decomposition of lithium peroxide, Li₂O₂ at 450°C^[2]

2Li₂O₂ → 2Li₂O + O₂

Structure

In the solid state lithium oxide adopts an antifluorite structure which is related to the CaF₂, fluorite structure with Li cations substituted for fluoride anions and oxide anions substituted for calcium cations.^[3] The ground state gas phase Li₂O molecule is linear with a bond length consistent with strong ionic bonding.^[4][5] VSEPR theory would predict a bent shape similar to H₂O.

Uses

Lithium oxide is used as a flux in ceramic glazes; and creates blues with copper and pinks with cobalt. Lithium oxide reacts with water and steam, forming lithium hydroxide and should be isolated from them.

Its usage is also being investigated for non-destructive emission spectroscopy evaluation and degradation monitoring within thermal barrier coating systems. It can be added as a co-dopant with yttria in the zirconia ceramic top coat, without a large decrease in expected service life of the coating. At high heat, lithium oxide emits a very detectable spectral pattern, which increases in intensity along with degradation of the coating. Implementation would allow in situ monitoring of such systems, enabling an efficient means to predict lifetime until failure or necessary maintenance.

A possible new use is as a replacement for lithium cobalt oxide as the cathode in the lithium ion batteries used to power electronic devices from mobile phones to laptop computers to battery-powered cars.^[6]

See also

• Lithium
• Lithium peroxide
• Lithium cobalt oxide

References

1. ^ Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN 0070494398
2. ^ ^{a b} Greenwood, Norman N.; Earnshaw, A. (1984). Chemistry of the Elements. Oxford: Pergamon. pp. 97–99. ISBN 0-08-022057-6. 
3. ^ Zintl, E.; Harder, A.; Dauth B. (1934). "Gitterstruktur der oxyde, sulfide, selenide und telluride des lithiums, natriums und kaliums". Zeitschrift für Elektrochemie und Angewandte Physikalische Chemie 40: 588–93. 
4. ^ Wells A.F. (1984) Structural Inorganic Chemistry 5th edition Oxford Science Publications ISBN 0-19-855370-6
5. ^ A spectroscopic determination of the bond length of the LiOLi molecule: Strong ionic bonding, D. Bellert, W. H. Breckenridge, J. Chem. Phys. 114, 2871 (2001); doi:10.1063/1.1349424
6. ^ "Air power". The Economist, Technology Quarterly. September 3, 2009. http://www.economist.com/search/displaystory.cfm?story_id=14299690. Retrieved September 9, 2009. 

External links

• CeramicMaterials.Info entry