Technical data for Cesium

Overview
NameCesium
SymbolCs
Atomic Number55
Atomic Weight132.90545
Density1.879 g/cm3
Melting Point28.44 °C
Boiling Point671 °C

Thermal properties
PhaseSolid
Melting Point28.44 °C
Boiling Point671 °C
Absolute Melting Point301.59 K
Absolute Boiling Point944 K
Critical Presure9.4 MPa (92.77 Atm)
Critical Temperature1938 K
Heat of Fusion2.09 kJ/mol
Heat of Vaporization65 kJ/mol
Heat of CombustionN/A
Specific Heat242 J/(kg K)[note]
Thermal Conductivity36 W/(m K)
Thermal ExpansionN/A

Bulk physical properties
Density1.879 g/cm3
Density (Liquid)1.843 g/cm3
Molar Volume0.000070732
Brinell Hardness0.14 MPa
Mohs Hardness0.2 MPa
Bulk Modulus1.6 GPa
Young Modulus1.7 GPa
Thermal Conductivity36 W/(m K)
Thermal ExpansionN/A

Reactivity
Valence1
Electronegativity0.79
ElectronAffinity45.5 kJ/mol
Ionization Energies
375.7, 2234.3, 3.4×103 kJ/mol

Health and Safety
Autoignition PointN/A
FlashpointN/A

Classifications
Alternate NamesCaesium
Nams of AllotropesNone
Blocks
Group1
Period6
Electron Configuration[Xe]6s1
ColorSilver
Discovery
1860 in Germany
Gas phaseN/A
CAS NumberCAS7440-46-2

Electrical properties
Electrical TypeConductor
Electrical Conductivity5×106 S/m
Resistivity2×10-7 m Ω
Superconducting PointN/A

Magnetic properties
Magnetic TypeN/A
Mass Magnetic Susceptibility-2.8×10-9
Molar Magnetic Susceptibility-3.72×10-10
Volume Magnetic Susceptibility-5.26×10-6

Abundances
% in Universe8×10-8%
% in Sun8×10-7%
% in Meteorites0.000014%
% in Earth's Crust0.00019%
% in Oceans5×10-8%
% in Humans2×10-6%

Atomic dimensions and structure
Atomic Radius298 pm
Covalent Radius225 pm
Van der Waals RadiusN/A
Crystal StructureBody Centered Cubic
Lattice Angles
π/2, π/2, π/2
Lattice Constants
614.1, 614.1, 614.1 pm
Space Group NameIm_ 3m
Space Group Number229

Nuclear Properties
Half-LifeStable
LifetimeStable
Stable Isotopes
133Cs
Isotopic Abundances
133Cs100%

Notes on the properties of Cesium:
Specific Heat: Value given for solid phase.