Lithium oxide
Chemical compound
From Wikipedia, the free encyclopedia
Lithium oxide (Li
2O), or lithia, is an inorganic chemical compound. It is a white or pale yellow solid. Although not specifically important, many materials are assessed on the basis of their Li2O content. For example, the Li2O content of the principal lithium mineral spodumene (LiAlSi2O6) is 8.03%.[2]
| Names | |
|---|---|
| IUPAC name
Lithium oxide | |
| Other names
Lithia Kickerite Dilithium Monoxide Dilithium Oxide | |
| Identifiers | |
3D model (JSmol) |
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| ChemSpider | |
| ECHA InfoCard | 100.031.823 |
PubChem CID |
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| RTECS number |
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| UNII | |
CompTox Dashboard (EPA) |
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| Properties | |
| Li 2O | |
| Molar mass | 29.88 g/mol |
| Appearance | white or pale yellow 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 to form LiOH | |
| log P | 9.23 |
Refractive index (nD) |
1.644 [1] |
| Structure | |
| Antifluorite (cubic), cF12 | |
| Fm3m, No. 225 | |
| Tetrahedral (Li+); cubic (O2−) | |
| Thermochemistry | |
Heat capacity (C) |
1.8105 J/g K or 54.1 J/mol K |
Std molar entropy (S⦵298) |
37.89 J/mol K |
Std enthalpy of formation (ΔfH⦵298) |
−20.01 kJ/g or −595.8 kJ/mol |
Gibbs free energy (ΔfG⦵) |
−562.1 kJ/mol |
| Hazards | |
| Occupational safety and health (OHS/OSH): | |
Main hazards |
Corrosive, reacts violently with water |
| NFPA 704 (fire diamond) | |
| Flash point | Non-flammable |
| Related compounds | |
Other anions |
Lithium sulfide Lithium selenide Lithium telluride Lithium polonide |
Other cations |
Sodium oxide Potassium oxide Rubidium oxide Caesium oxide |
| Lithium peroxide Lithium superoxide | |
Related compounds |
Lithium hydroxide |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Production

Lithium oxide forms along with small amounts of lithium peroxide when lithium metal is burned in the air and combines with oxygen at temperatures above 100 °C:[3]
- 4Li + O
2 → 2Li
2O.
Pure Li
2O can be produced by the thermal decomposition of lithium peroxide, Li
2O
2, at 450 °C[3][2]
- 2Li
2O
2 → 2Li
2O + O
2
Structure
Solid lithium oxide adopts an antifluorite structure with four-coordinated Li+ centers and eight-coordinated oxides.[4]
The ground state gas phase Li
2O molecule is linear with a bond length consistent with strong ionic bonding.[5][6] VSEPR theory would predict a bent shape similar to H
2O.
Uses
Reactions
Lithium oxide absorbs carbon dioxide forming lithium carbonate:
- Li
2O + CO
2 → Li
2CO
3
The oxide reacts slowly with water, forming lithium hydroxide:
- Li
2O + H
2O → 2LiOH




