Caesium monoxide or caesium oxide is a chemical compound with the chemical formula Cs2O. It is the simplest and most common oxide of the caesium. It forms yellow-orange hexagonal crystals.[1]
 Caesium cations, Cs+ Oxide anions, O2− | |
| Names | |
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| IUPAC name
Caesium oxide
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| Other names
Cesium oxide (US)
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| Identifiers | |
3D model (JSmol)
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| ChemSpider | |
| ECHA InfoCard | 100.039.693 |
| EC Number |
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PubChem CID
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| Properties | |
| Cs2O | |
| Molar mass | 281.810 g·mol−1 |
| Appearance | Yellow-orange solid |
| Density | 4.65 g/cm3, solid |
| Melting point | 490 °C (914 °F; 763 K) (under N2) |
| Reacts to form CsOH | |
| 1534.0·10−6 cm3/mol | |
| Structure | |
| anti-CdCl2 (hexagonal) | |
| Thermochemistry | |
Heat capacity (C)
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76.0 J/(K·mol) |
Std molar
entropy (S⦵298) |
146.9 J/(K·mol) |
Std enthalpy of
formation (ΔfH⦵298) |
−345.8 kJ/mol |
| Hazards | |
| Occupational safety and health (OHS/OSH): | |
Main hazards
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Corrosive and Superbase |
| GHS labelling: | |
 
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| NFPA 704 (fire diamond) | |
| Flash point | non-flammable |
| Related compounds | |
Other anions
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Other cations
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Related compounds
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Caesium 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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Uses
editCaesium oxide is used in photocathodes to detect infrared signals in devices such as image intensifiers, vacuum photodiodes, photomultipliers, and TV camera tubes[3] L. R. Koller described the first modern photoemissive surface in 1929–1930 as a layer of caesium on a layer of caesium oxide on a layer of silver.[4] It is a good electron emitter; however, its high vapor pressure limits its usefulness.[5]
Reactions
editElemental magnesium reduces caesium oxide to elemental caesium, forming magnesium oxide as a side-product:[6][7]
- Cs2O + Mg → 2 Cs + MgO
Cs2O is hygroscopic, forming the corrosive CsOH on contact with water.
References
edit- ^ a b Lide, David R., ed. (2006). CRC Handbook of Chemistry and Physics (87th ed.). Boca Raton, FL: CRC Press. pp. 451, 514. ISBN 0-8493-0487-3..
- ^ Greenwood, Norman N.; Earnshaw, Alan (1984). Chemistry of the Elements. Oxford: Pergamon Press. pp. 97–100. ISBN 978-0-08-022057-4..
- ^ Capper, Peter; Elliott, C. T. (2000), Infrared Detectors and Emitters, Springer, p. 14, ISBN 978-0-7923-7206-6
- ^ Busch, Kenneth W.; Busch, Marianna A. (1990), Multielement Detection Systems for Spectrochemical Analysis, Wiley-Interscience, p. 12, ISBN 978-0-471-81974-5
- ^ Boolchand, Punit, ed. (2000), Insulating and Semiconducting Glasses, World Scientific, p. 855, Bibcode:2000isg..book.....B, ISBN 978-981-02-3673-1
- ^ Turner Jr., Francis M., ed. (1920), The Condensed Chemical Dictionary, New York: Chemical Catalog Co., p. 121
- ^ Arora, M.G. (1997), S-Block Elements, New Delhi: Anmol Publications, p. 13, ISBN 978-81-7488-562-3