Caesium oxide
Caesium oxide | |
---|---|
IUPAC name | Caesium oxide |
Identifiers | |
InChI | InChI=1/2Cs.O/q2*+1;-2 |
InChIKey | KOPBYBDAPCDYFK-UHFFFAOYAW |
Standard InChI | InChI=1S/2Cs.O/q2*+1;-2 |
Standard InChIKey | KOPBYBDAPCDYFK-UHFFFAOYSA-N |
CAS number | [ ] |
EC number | |
ChemSpider | |
Properties[1] | |
Chemical formula | Cs2O |
Molar mass | 281.81 g/mol |
Appearance | yellow-orange solid |
Density | 4.25 g/cm3, solid |
Melting point |
490 °C (under N2) |
Solubility in water | reacts |
Structure[2] | |
Crystal structure | anti-CdCl2 (hexagonal) |
Coordination geometry | Octahedral (O2-) |
Thermochemistry | |
Std enthalpy of formation ΔfH |
-345.8 kJ/mol |
Standard molar entropy S |
146.9 J K-1 mol-1 |
Specific heat capacity C | 76.0 J K-1 mol-1 |
Hazards | |
EU index number | not listed |
Flash point | non-flammable |
Related compounds | |
Other anions | Caesium hydroxide |
Other cations | Lithium oxide Sodium oxide Potassium oxide Rubidium oxide |
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
Caesium oxide is one of several binary compounds of caesium and oxygen. It has the formula Cs2O, and forms yellow-orange hexagonal crystals.[1]
Uses
Caesium 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 1929–30 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
Elemental magnesium reduces caesium oxide to elemental caesium:[6][7]
- Cs2O + Mg → 2Cs + MgO
When heated in air, caesium oxide decomposes at around 400 ºC, before it melts: its melting point (490 ºC) must be determined under an atomsphere of nitrogen.[1]
References
- ↑ 1.0 1.1 1.2 CRC Handbook of Chemistry and Physics, 62nd ed.; Weast, Robert C., Ed.; CRC Press: Boca Raton, FL, 1981; p B-92. ISBN 0-8493-0462-8.
- ↑ Greenwood, Norman N.; Earnshaw, A. Chemistry of the Elements; Pergamon: Oxford, 1984; pp 97–100. ISBN 0-08-022057-6.
- ↑ Capper, Peter; Elliott, C. T. Infrared Detectors and Emitters; Springer, 2000; p 14. ISBN 9780792372066
- ↑ Busch, Kenneth W.; Busch, Marianna A. Multielement Detection Systems for Spectrochemical Analysis; Wiley-Interscience, 1990; p 12. ISBN 9780471819745
- ↑ Insulating and Semiconducting Glasses; Boolchand, Punit, Ed.; World Scientific, 2000; p 855. ISBN 9789810236731
- ↑ The Condensed Chemical Dictionary; Turner, Jr., Francis M., Ed.; Chemical Catalog Co.: New York, 1920; p 121
- ↑ Arora, M.G. S-Block Elements; Anmol: New Delhi, 1997; p 13. ISBN 9788174885623
Error creating thumbnail: Unable to save thumbnail to destination | This page was originally imported from Wikipedia, specifically this version of the article "Caesium oxide". Please see the history page on Wikipedia for the original authors. This WikiChem article may have been modified since it was imported. It is licensed under the Creative Commons Attribution–Share Alike 3.0 Unported license. |