Chemistry:Caesium monoxide

From HandWiki
Caesium oxide[1][2]
Caesium oxide
  Caesium cations, Cs+
  Oxide anions, O2−
Names
IUPAC name
Caesium oxide
Other names
Cesium oxide (United States )
Identifiers
3D model (JSmol)
ChemSpider
EC Number
  • 243-679-0
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 N
2
)
Reacts to form CsOH
1534.0·10−6 cm3/mol
Structure
anti-CdCl
2
(hexagonal)
Thermochemistry
76.0 J/(K·mol)
146.9 J/(K·mol)
−345.8 kJ/mol
Hazards
Main hazards Corrosive
GHS pictograms GHS05: CorrosiveGHS08: Health hazard
NFPA 704 (fire diamond)
Flammability code 0: Will not burn. E.g. waterHealth code 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasReactivity code 2: Undergoes violent chemical change at elevated temperatures and pressures, reacts violently with water, or may form explosive mixtures with water. E.g. white phosphorusSpecial hazard W: Reacts with water in an unusual or dangerous manner. E.g. sodium, sulfuric acidNFPA 704 four-colored diamond
0
3
2
Flash point non-flammable
Related compounds
Other anions
Other cations
Related caesium oxides
Related compounds
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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Infobox references

Caesium monoxide or caesium oxide is an chemical compound with the chemical formula Cs
2
O
. It is the simplest and most common oxide of the caesium. It 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 1929–1930 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

Elemental magnesium reduces caesium oxide to elemental caesium, forming magnesium oxide as a side-product:[6][7]

Cs
2
O + Mg → 2 Cs + MgO

Cs
2
O
is hygroscopic, forming the corrosive CsOH on contact with water.

References

  1. 1.0 1.1 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. .
  2. Greenwood, Norman N.; Earnshaw, Alan (1984). Chemistry of the Elements. Oxford: Pergamon Press. pp. 97–100. ISBN 978-0-08-022057-4. https://books.google.com/books?id=OezvAAAAMAAJ&q=0-08-022057-6&dq=0-08-022057-6&source=bl&ots=m4tIRxdwSk&sig=XQTTjw5EN9n5z62JB3d0vaUEn0Y&hl=en&sa=X&ei=UoAWUN7-EM6ziQfyxIDoCQ&ved=0CD8Q6AEwBA. .
  3. Capper, Peter; Elliott, C. T. (2000), Infrared Detectors and Emitters, Springer, p. 14, ISBN 978-0-7923-7206-6, https://books.google.com/books?id=HtgEcjQcgkkC&q=%22cesium+oxide%22+OR+%22caesium+oxide%22&pg=PA14 
  4. Busch, Kenneth W.; Busch, Marianna A. (1990), Multielement Detection Systems for Spectrochemical Analysis, Wiley-Interscience, p. 12, ISBN 978-0-471-81974-5, https://books.google.com/books?id=9H0W1J-Rku4C&q=%22cesium+oxide%22+OR+%22caesium+oxide%22&pg=PA12 
  5. Boolchand, Punit, ed. (2000), Insulating and Semiconducting Glasses, World Scientific, p. 855, ISBN 978-981-02-3673-1, Bibcode2000isg..book.....B, https://books.google.com/books?id=QK2f4eVh7qgC&q=%22cesium+oxide%22+OR+%22caesium+oxide%22&pg=PA855 
  6. Turner Jr., Francis M., ed. (1920), The Condensed Chemical Dictionary, New York: Chemical Catalog Co., p. 121, https://books.google.com/books?id=y8y0XE0nsYEC&q=%22cesium+oxide%22+OR+%22caesium+oxide%22&pg=PA121 
  7. Arora, M.G. (1997), S-Block Elements, New Delhi: Anmol Publications, p. 13, ISBN 978-81-7488-562-3, https://books.google.com/books?id=QR3TCaKaykEC&q=%22Bromine+dioxide%22&pg=PA256