Difference between revisions of "Caesium oxide"
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+ | {{about|the compound Cs<sub>2</sub>O|other binary compounds of caesium and oxygen}} | ||
{{Chembox | {{Chembox | ||
− | |||
| Name = Caesium oxide | | Name = Caesium oxide | ||
| ImageFile = Caesium-oxide-xtal-3D-vdW.png | | ImageFile = Caesium-oxide-xtal-3D-vdW.png | ||
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| ImageName = Caesium oxide | | ImageName = Caesium oxide | ||
| IUPACName = Caesium oxide | | IUPACName = Caesium oxide | ||
− | | OtherNames = | + | | OtherNames = |
| Section1 = {{Chembox Identifiers | | Section1 = {{Chembox Identifiers | ||
| InChI = 1/2Cs.O/q2*+1;-2 | | InChI = 1/2Cs.O/q2*+1;-2 | ||
+ | | StdInChI = 1S/2Cs.O/q2*+1;-2 | ||
+ | | InChIKey = KOPBYBDAPCDYFK-UHFFFAOYAW | ||
+ | | StdInChIKey = KOPBYBDAPCDYFK-UHFFFAOYSA-N | ||
| CASNo = 20281-00-9 | | CASNo = 20281-00-9 | ||
| CASNo_Ref = {{cascite}} | | CASNo_Ref = {{cascite}} | ||
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}} | }} | ||
| Section2 = {{Chembox Properties | | Section2 = {{Chembox Properties | ||
+ | | Reference = <ref name="CRC">{{RubberBible62nd|page=B-92}}.</ref> | ||
| Formula = Cs<sub>2</sub>O | | Formula = Cs<sub>2</sub>O | ||
| MolarMass = 281.81 g/mol | | MolarMass = 281.81 g/mol | ||
| Appearance = yellow-orange solid | | Appearance = yellow-orange solid | ||
− | | Density = 4. | + | | Density = 4.25 g/cm<sup>3</sup>, solid |
− | | Solubility = | + | | Solubility = reacts |
| MeltingPt = 490 °C (under N<sub>2</sub>) | | MeltingPt = 490 °C (under N<sub>2</sub>) | ||
| BoilingPt = | | BoilingPt = | ||
}} | }} | ||
| Section3 = {{Chembox Structure | | Section3 = {{Chembox Structure | ||
− | | Coordination = | + | | Reference = <ref name="G&E">{{Greenwood&Earnshaw1st|pages=97–100}}.</ref> |
− | | CrystalStruct = [[Cadmium chloride|anti-CdCl<sub>2</sub>]] ([[Hexagonal crystal system|hexagonal]]) | + | | Coordination = Octahedral (O<sup>2-</sup>) |
+ | | CrystalStruct = [[Cadmium chloride structure|anti-CdCl<sub>2</sub>]] ([[Hexagonal crystal system|hexagonal]]) | ||
}} | }} | ||
| Section4 = {{Chembox Thermochemistry | | Section4 = {{Chembox Thermochemistry | ||
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}} | }} | ||
− | '''Caesium oxide''' | + | '''Caesium oxide''' is one of several binary compounds of [[caesium]] and [[oxygen]]. It has the formula Cs<sub>2</sub>O, and forms yellow-orange [[Hexagonal crystal system|hexagonal]] crystals.<ref name="CRC"/> |
==Uses== | ==Uses== | ||
− | Caesium oxide is used in [[photocathode]]s to detect [[infrared]] signals in devices such as [[image intensifier]]s, vacuum [[photodiode]]s, [[photomultiplier]]s, and [[TV camera]] tubes<ref name="inf">{{Citation | last1 = Capper | first1 = Peter | last2 = Elliott | first2 = C. T. | year = 2000 | title = Infrared Detectors and Emitters | publisher = Springer | isbn = 9780792372066 | page = 14 | + | Caesium oxide is used in [[photocathode]]s to detect [[infrared]] signals in devices such as [[image intensifier]]s, vacuum [[photodiode]]s, [[photomultiplier]]s, and [[TV camera]] tubes<ref name="inf">{{Citation | last1 = Capper | first1 = Peter | last2 = Elliott | first2 = C. T. | year = 2000 | title = Infrared Detectors and Emitters | publisher = Springer | isbn = 9780792372066 | page = 14}}</ref> |
− | 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]].<ref name="mul">{{Citation | last = Busch | first = Kenneth W. | last2 = Busch | first2 =Marianna A. | year = 1990 | title = Multielement Detection Systems for Spectrochemical Analysis | publisher = Wiley-Interscience | isbn = 9780471819745 | page = 12 | + | 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]].<ref name="mul">{{Citation | last = Busch | first = Kenneth W. | last2 = Busch | first2 =Marianna A. | year = 1990 | title = Multielement Detection Systems for Spectrochemical Analysis | publisher = Wiley-Interscience | isbn = 9780471819745 | page = 12}}</ref> It is a good [[electron]] emitter; however, its high [[vapor pressure]] limits its usefulness<ref name="ins">{{Citation | editor-first = Punit | editor-last = Boolchand | year = 2000 | title = Insulating and Semiconducting Glasses | publisher = World Scientific | isbn = 9789810236731 | page = 855}}</ref>. |
==Reactions== | ==Reactions== | ||
Elemental [[magnesium]] [[Redox|reduces]] caesium oxide to elemental caesium:<ref name="cond"> | Elemental [[magnesium]] [[Redox|reduces]] caesium oxide to elemental caesium:<ref name="cond"> | ||
− | {{Citation | editor-last= Turner, Jr. | editor-first= Francis M. | year = 1920 | title = The Condensed Chemical Dictionary | publication-place = New York | publisher = Chemical Catalog Co. | page = 121 | + | {{Citation | editor-last= Turner, Jr. | editor-first= Francis M. | year = 1920 | title = The Condensed Chemical Dictionary | publication-place = New York | publisher = Chemical Catalog Co. | page = 121}}</ref><ref name="sblock">{{Citation | last = Arora | first = M.G. | year = 1997 | title = S-Block Elements | publication-place = New Delhi | publisher = Anmol | isbn = 9788174885623 | page = 13}}</ref> |
− | {{Citation | last = Arora | first = M.G. | year = 1997 | title = S-Block Elements | publication-place = New Delhi | publisher = Anmol | + | :Cs<sub>2</sub>O + Mg → 2Cs + MgO |
− | :Cs<sub>2</sub>O + Mg → | ||
==References== | ==References== |
Revision as of 15:27, 25 August 2009
This article is about the compound Cs2O. For other binary compounds of caesium and oxygen, see Caesium oxide (disambiguation).
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
References
- ↑ 1.0 1.1 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
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