Caesium oxide
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| Names | |
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IUPAC name
Caesium oxide
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| Other names
Cesium oxide (US)
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| Identifiers | |
20281-00-9 
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| 3D model (Jmol) | Interactive image |
| ChemSpider |
8079519
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| ECHA InfoCard | 100.039.693 |
| EC Number | 243-679-0 |
| PubChem | 9903865 |
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| Properties | |
| Cs2O | |
| Molar mass | 281.81 g/mol |
| Appearance | yellow-orange solid |
| Density | 4.65 g/cm3, solid |
| Melting point | 490 °C (914 °F; 763 K) (under N2) |
| reacts violently to form CsOH | |
| +1534.0·10−6 cm3/mol | |
| Structure | |
| anti-CdCl2 (hexagonal) | |
| Thermochemistry | |
| 76.0 J K−1 mol−1 | |
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Std molar
entropy (S |
146.9 J K−1 mol−1 |
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Std enthalpy of
formation (ΔfH |
-345.8 kJ/mol |
| Hazards | |
| Flash point | non-flammable |
| Related compounds | |
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Other anions
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Caesium hydroxide |
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Other cations
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Lithium oxide Sodium oxide Potassium oxide Rubidium oxide |
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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 (what is  ?) |
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| Infobox references | |
Caesium oxide (IUPAC name) or cesium oxide describes inorganic compounds composed of caesium and oxygen. The following binary (containing only Cs and O) oxides of caesium are known: Cs11O3, Cs4O, Cs7O, and Cs2O. Both the oxide and suboxides are brightly coloured. The species Cs2O forms yellow-orange hexagonal crystals.
Caesium oxide is used in to detect infrared signals in devices such as image intensifiers, vacuum photodiodes, photomultipliers, and TV camera tubes L. R. Koller described the first modern photoemissive surface in 1929–30 as a layer of caesium on a layer of caesium oxide on a layer of silver. It is a good electron emitter; however, its high vapor pressure limits its usefulness.
Elemental magnesium reduces caesium oxide to elemental caesium, forming magnesium oxide as a side-product:
Cs2O is hygroscopic, forming the corrosive CsOH on contact with water.
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Wikipedia