Caesium, 00Cs
Some pale gold metal, with a liquid-like texture and lustre, sealed in a glass ampoule
Caesium
Pronunciation/ˈsziəm/ (SEE-zee-əm)
Alternative namecesium (US)
Appearancepale gold
Standard atomic weight Ar°(Cs)
Caesium in the periodic table
HydrogenHelium
LithiumBerylliumBoronCarbonNitrogenOxygenFluorineNeon
SodiumMagnesiumAluminiumSiliconPhosphorusSulfurChlorineArgon
PotassiumCalciumScandiumTitaniumVanadiumChromiumManganeseIronCobaltNickelCopperZincGalliumGermaniumArsenicSeleniumBromineKrypton
RubidiumStrontiumYttriumZirconiumNiobiumMolybdenumTechnetiumRutheniumRhodiumPalladiumSilverCadmiumIndiumTinAntimonyTelluriumIodineXenon
CaesiumBariumLanthanumCeriumPraseodymiumNeodymiumPromethiumSamariumEuropiumGadoliniumTerbiumDysprosiumHolmiumErbiumThuliumYtterbiumLutetiumHafniumTantalumTungstenRheniumOsmiumIridiumPlatinumGoldMercury (element)ThalliumLeadBismuthPoloniumAstatineRadon
FranciumRadiumActiniumThoriumProtactiniumUraniumNeptuniumPlutoniumAmericiumCuriumBerkeliumCaliforniumEinsteiniumFermiumMendeleviumNobeliumLawrenciumRutherfordiumDubniumSeaborgiumBohriumHassiumMeitneriumDarmstadtiumRoentgeniumCoperniciumNihoniumFleroviumMoscoviumLivermoriumTennessineOganesson
Rb

Cs

Fr
xenoncaesiumbarium
Groupgroup 1: hydrogen and alkali metals
Periodperiod 6
Block  s-block
Electron configuration[Xe] 6s1
Electrons per shell2, 8, 18, 18, 8, 1
Physical properties
Phase at STPsolid
Melting point301.7 K ​(28.5 °C, ​83.3 °F)
Boiling point944 K ​(671 °C, ​1240 °F)
Density (near r.t.)1.93 g/cm3
when liquid (at m.p.)1.843 g/cm3
Critical point1938 K, 9.4 MPa[3]
Heat of fusion2.09 kJ/mol
Heat of vaporization63.9 kJ/mol
Molar heat capacity32.210 J/(mol·K)
Vapor pressure
P (Pa)1101001 k10 k100 k
at T (K)418469534623750940
Atomic properties
Oxidation states−1, +1[4] (a strongly basic oxide)
ElectronegativityPauling scale: 0.79
Ionization energies
  • 1st: 375.7 kJ/mol
  • 2nd: 2234.3 kJ/mol
  • 3rd: 3400 kJ/mol
Atomic radiusempirical: 265 pm
Covalent radius244±11 pm
Van der Waals radius343 pm
Color lines in a spectral range
Spectral lines of caesium
Other properties
Natural occurrenceprimordial
Crystal structurebody-centered cubic (bcc)
Bodycentredcubic crystal structure for caesium
Thermal expansion97 µm/(m⋅K) (at 25 °C)
Thermal conductivity35.9 W/(m⋅K)
Electrical resistivity205 nΩ⋅m (at 20 °C)
Magnetic orderingparamagnetic[5]
Young's modulus1.7 GPa
Bulk modulus1.6 GPa
Mohs hardness0.2
Brinell hardness0.14 MPa
CAS Number7440-46-2
History
Discovery1860
First isolationCarl Setterberg (1882)
Isotopes of caesium
Main isotopes[6]Decay
abun­dancehalf-life (t1/2)modepro­duct
131Cssynth9.7 dε131Xe
133Cs100%stable
134Cssynth2.0648 yε134Xe
β134Ba
135Cstrace1.33×106 yβ135Ba
137Cssynth30.17 y[7]β137Ba
 Category: Caesium
| references
Cs · Caesium
Xe ←

ibox Xe

iso
55
Cs  [e]
IB-Cs [e]
IBisos [e]
→ Ba

ibox Ba

indexes by PT (page)
child table, as reused in {IB-Cs}
Main isotopes of caesium
Main isotopes[6]Decay
abun­dancehalf-life (t1/2)modepro­duct
131Cssynth9.7 dε131Xe
133Cs100%stable
134Cssynth2.0648 yε134Xe
β134Ba
135Cstrace1.33×106 yβ135Ba
137Cssynth30.17 y[7]β137Ba
Data sets read by {{Infobox element}}
Name and identifiers
Symbol etymology (11 non-trivial)
Top image (caption, alt)
Pronunciation
Allotropes (overview)
Group (overview)
Period (overview)
Block (overview)
Natural occurrence
Phase at STP
Oxidation states
Spectral lines image
Electron configuration (cmt, ref)
Isotopes
Standard atomic weight
  most stable isotope
Wikidata
Wikidata *
* Not used in {{Infobox element}} (2023-01-01)
See also {{Index of data sets}} · Cat:data sets (45) · (this table: )

References

  1. ^ "Standard Atomic Weights: Caesium". CIAAW. 2013.
  2. ^ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.
  3. ^ Haynes, William M., ed. (2011). CRC Handbook of Chemistry and Physics (92nd ed.). Boca Raton, FL: CRC Press. p. 4.121. ISBN 1-4398-5511-0.
  4. ^ Dye, J. L. (1979). "Compounds of Alkali Metal Anions". Angewandte Chemie International Edition. 18 (8): 587–598. doi:10.1002/anie.197905871.
  5. ^ "Magnetic susceptibility of the elements and inorganic compounds". Handbook of Chemistry and Physics (PDF) (87th ed.). CRC press. ISBN 0-8493-0487-3. Retrieved 2010-09-26.
  6. ^ a b Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
  7. ^ a b "NIST Radionuclide Half-Life Measurements". NIST. Retrieved 2011-03-13.