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
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| Reference = <ref name="CRC">{{RubberBible87th|pages=451, 514}}.</ref><ref name="G&E">{{Greenwood&Earnshaw1st|pages=97–100}}.</ref>
 
 
| 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
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|  OtherNames = Cesium oxide ([[United States|US]])
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|  OtherNames =  
 
| Section1 = {{Chembox Identifiers
 
| Section1 = {{Chembox Identifiers
 
|  InChI = 1/2Cs.O/q2*+1;-2
 
|  InChI = 1/2Cs.O/q2*+1;-2
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|  StdInChI = 1S/2Cs.O/q2*+1;-2
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|  InChIKey = KOPBYBDAPCDYFK-UHFFFAOYAW
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|  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
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|  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
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|  Density = 4.65 g/cm<sup>3</sup>, solid
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|  Density = 4.25 g/cm<sup>3</sup>, solid
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|  Solubility = very soluble in water
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|  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
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|  Coordination =
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|  Reference = <ref name="G&E">{{Greenwood&Earnshaw1st|pages=97–100}}.</ref>
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|  CrystalStruct = [[Cadmium chloride|anti-CdCl<sub>2</sub>]] ([[Hexagonal crystal system|hexagonal]])
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|  Coordination = Octahedral (O<sup>2-</sup>)
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|  CrystalStruct = [[Cadmium chloride structure|anti-CdCl<sub>2</sub>]] ([[Hexagonal crystal system|hexagonal]])
 
   }}
 
   }}
 
| Section4 = {{Chembox Thermochemistry
 
| Section4 = {{Chembox Thermochemistry
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}}
 
}}
  
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'''Caesium oxide''' ([[IUPAC]] name) or '''cesium oxide''' describes [[inorganic compound]]s composed of [[caesium]] and [[oxygen]]. The following binary (containing only Cs and O) oxides of caesium are known: Cs<sub>11</sub>O<sub>3</sub>, Cs<sub>4</sub>O, Cs<sub>7</sub>O, and Cs<sub>2</sub>O.<ref name=Simon>{{citation | last = Simon | first = A. | title = Group 1 and 2 Suboxides and Subnitrides — Metals with Atomic Size Holes and Tunnels | journal = Coord. Chem. Rev. | year = 1997 | volume = 163 | pages = 253–270 | doi = 10.1016/S0010-8545(97)00013-1}}.</ref>. Both the oxide and [[suboxide]]s are brightly coloured.  The species Cs<sub>2</sub>O forms yellow-orange [[Hexagonal crystal system|hexagonal]] crystals.<ref name="CRC"/>
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'''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==
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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 | url = http://books.google.com/books?id=HtgEcjQcgkkC&pg=PA14&dq=%22cesium+oxide%22+OR+%22caesium+oxide%22&lr=&as_drrb_is=b&as_minm_is=1&as_miny_is=2000&as_maxm_is=12&as_maxy_is=2009&as_brr=3&as_pt=ALLTYPES&ei=2nrASdqVM46syASCgN3SBA&client=firefox-a#PPA14,M1}}</ref>
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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>
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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 | url = http://books.google.com/books?id=9H0W1J-Rku4C&pg=PA12&dq=%22cesium+oxide%22+OR+%22caesium+oxide%22&lr=&as_drrb_is=q&as_minm_is=1&as_miny_is=1776&as_maxm_is=12&as_maxy_is=2009&as_brr=3&as_pt=ALLTYPES&ei=wILASe63I5K8zATZtPHGBA&client=firefox-a}}</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 | url = http://books.google.com/books?id=QK2f4eVh7qgC&pg=PA855&dq=%22cesium+oxide%22+OR+%22caesium+oxide%22&lr=&as_drrb_is=b&as_minm_is=1&as_miny_is=2000&as_maxm_is=12&as_maxy_is=2009&as_brr=3&as_pt=ALLTYPES&ei=1HzASbD0BpX8ygTl4MTODQ&client=firefox-a}}</ref>.
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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">
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{{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 | url = http://books.google.com/books?id=y8y0XE0nsYEC&pg=PA121&dq=%22cesium+oxide%22+OR+%22caesium+oxide%22&lr=&as_drrb_is=q&as_minm_is=1&as_miny_is=1776&as_maxm_is=12&as_maxy_is=2009&as_brr=3&as_pt=ALLTYPES&ei=rIDAScrTMIPmzASo-si9Ag&client=firefox-a#PPA121,M1}}</ref><ref name="sblock">
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{{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>
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{{Citation | last = Arora | first = M.G. | year = 1997 | title = S-Block Elements | publication-place = New Delhi | publisher = Anmol Publications | isbn = 9788174885623 | page = 13 | url = http://books.google.com/books?id=QR3TCaKaykEC&pg=PA256&dq=%22Bromine+dioxide%22&as_brr=3&ei=K1PASaLLEIu6yQSGj_CnAQ& |  url= http://books.google.com/books?id=XPuh2knuV6EC&pg=PA30&dq=%22cesium+oxide%22+OR+%22caesium+oxide%22+pollucite&lr=&as_brr=3&as_pt=ALLTYPES&ei=G4TASZWJIqSayASz6eGWAg&client=firefox-a#PPA30,M1}}</ref>
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:Cs<sub>2</sub>O  +  Mg  → 2Cs + MgO
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:Cs<sub>2</sub>O  +  Mg  →   Cs + [[magnesium oxide|MgO]]
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When heated in air, caesium oxide decomposes at around 400&nbsp;ºC, before it melts: its melting point (490&nbsp;ºC) must be determined under an atomsphere of [[nitrogen]].<ref name="CRC"/>
  
 
==References==
 
==References==

Latest revision as of 15:33, 25 August 2009

This article is about the compound Cs2O. For other binary compounds of caesium and oxygen, see Caesium oxide (disambiguation).
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 [20281-00-9]
EC number 243-679-0
ChemSpider 8079519
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 ΔfHo298 -345.8 kJ/mol
Standard molar entropy So298 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. ↑ 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.
  2. ↑ Greenwood, Norman N.; Earnshaw, A. Chemistry of the Elements; Pergamon: Oxford, 1984; pp 97–100. ISBN 0-08-022057-6.
  3. ↑ Capper, Peter; Elliott, C. T. Infrared Detectors and Emitters; Springer, 2000; p 14. ISBN 9780792372066
  4. ↑ Busch, Kenneth W.; Busch, Marianna A. Multielement Detection Systems for Spectrochemical Analysis; Wiley-Interscience, 1990; p 12. ISBN 9780471819745
  5. ↑ Insulating and Semiconducting Glasses; Boolchand, Punit, Ed.; World Scientific, 2000; p 855. ISBN 9789810236731
  6. ↑ The Condensed Chemical Dictionary; Turner, Jr., Francis M., Ed.; Chemical Catalog Co.: New York, 1920; p 121
  7. ↑ Arora, M.G. S-Block Elements; Anmol: New Delhi, 1997; p 13. ISBN 9788174885623
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