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| Names | |
|---|---|
| IUPAC name Lithium oxide | |
| Other names Lithia Kickerite Dilithium Monoxide Dilithium Oxide | |
| Identifiers | |
3D model (JSmol) | |
| ChemSpider |
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| ECHA InfoCard | 100.031.823 |
| RTECS number |
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| UNII | |
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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 formLiOH | |
| logP | 9.23 |
Refractive index (nD) | 1.644[1] |
| Structure | |
| Antifluorite (cubic),cF12 | |
| Fm3m, No. 225 | |
| Tetrahedral (Li+); cubic (O2−) | |
| Thermochemistry | |
| 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 | |
Otheranions | Lithium sulfide Lithium selenide Lithium telluride Lithium polonide |
Othercations | 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 theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Lithium oxide (Li
2O) orlithia is aninorganic 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 mineralspodumene (LiAlSi2O6) is 8.03%.[2]
Lithium oxide forms along with small amounts oflithium peroxide when lithium metal is burned in the air and combines with oxygen at temperatures above 100 °C:[3]
PureLi
2O can be produced by thethermal decomposition oflithium peroxide,Li
2O
2, at 450 °C[3][2]
Solid lithium oxide adopts an antifluorite structure with four-coordinated Li+ centers and eight-coordinated oxides.[4]
The ground state gas phaseLi
2O molecule is linear with a bond length consistent with strong ionic bonding.[5][6]VSEPR theory would predict a bent shape similar toH
2O.
Lithium oxide is used as aflux in ceramic glazes; and creates blues withcopper and pinks withcobalt. Lithium oxide reacts withwater andsteam, forminglithium hydroxide and should be isolated from them.
Its usage is also being investigated for non-destructive emission spectroscopy evaluation and degradation monitoring withinthermal barrier coating systems. It can be added as a co-dopant withyttria 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.
Lithium oxide absorbscarbon dioxide forminglithium carbonate:
The oxide reacts slowly with water, forminglithium hydroxide:
