Lithium oxide

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Lithium oxide
Lithium-oxide-unit-cell-3D-balls-B.png
Names
IUPAC name
Lithium oxide
Other names
Kickerite
Identifiers
12057-24-8 YesY
ChemSpider 145811 YesY
Jmol-3D images Image
PubChem 166630
RTECS number OJ6360000
Properties
Li
2
O
Molar mass 29.88 g/mol
Appearance white solid
Density 2.013 g/cm3
Melting point 1,438 °C (2,620 °F; 1,711 K)
Boiling point 2,600 °C (4,710 °F; 2,870 K)
reacts violently to form LiOH
log P 9.23
1.644 [1]
Structure
Crystal structure Antifluorite (cubic), cF12
Space group Fm3m, No. 225
Tetrahedral (Li+); cubic (O2−)
Thermochemistry
1.8105 J/g K or 54.1 J/mol K
37.89 J/mol K
-20.01 kJ/g or -595.8 kJ/mol
-562.1 kJ/mol
Hazards
Main hazards Corrosive, reacts violently with water
EU Index Not listed
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
Except where noted otherwise, data is given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

Lithium oxide (Li
2
O) 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 + O
2
→ 2Li
2
O
.

Pure Li
2
O
can be produced by the thermal decomposition of lithium peroxide, Li
2
O
2
, at 450 °C[2]

2Li
2
O
2
→ 2Li
2
O
+ O
2

Structure[edit]

In the solid state lithium oxide adopts an antifluorite structure which is related to the CaF
2
, fluorite structure with Li cations substituted for fluoride anions and oxide anions substituted for calcium cations.[3] The ground state gas phase Li
2
O
molecule is linear with a bond length consistent with strong ionic bonding.[4][5] VSEPR theory would predict a bent shape similar to H
2
O
.

Uses[edit]

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.

Lithium metal might be obtained from lithium oxide by electrolysis, releasing oxygen as by-product.

See also[edit]

References[edit]

  1. ^ Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN 0-07-049439-8
  2. ^ a b Greenwood, Norman N.; Earnshaw, Alan (1984). Chemistry of the Elements. Oxford: Pergamon Press. 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

External links[edit]