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Atomic: M.A.C. | Reference
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Caesium
Electrons per shell 2,8,18,18,8,1
Electron Configuration [Xe] 6s1 open electron config
Ground state 2S1/2
Atomic Volume 71.07 cm3 mol-1
Electronegativity 0.79
Magnetic ordering No data
Mass magnetic susceptibility -2.8 x 10-9
Molar magnetic susceptibility -3.72 x 10-10
Thermal Properties
Enthalpy of Atomization 78.2 kJ mol-1 @25°C
Enthalpy of Fusion 2.09 kJ mol-1
Enthalpy of Vaporisation 66.5 kJ mol-1
Heat Capacity 32.210 J mol-1 K-1
Thermal Conductivity 35.9 W m-1 K-1
Thermal Expansion 97 μm m-1 K-1
Hardness
Brinell hardness 0.14 MPa
Mohs hardness 0.2
Elastic Properties
Bulk modulus 1.6 GPa
Young's modulus 1.7 GPa
Electrical Properties
Electrical resistivity 2.0 x 10-7 Ω m
Electrical conductivity 0.0489 106/cm Ω
Chemical Properties
Electrochemical Equivalent 4.9587 g Ah-1
Electron Work Function 2.14 eV
Valence Electron Potential (-eV) 8.62
Ionization Potential  
First 3.894
Second 25.1
Energy Levels
Kα1 (intensity 100) 30.9728 KeV
Kα2 (intensity 50) 30.6251 KeV
Kβ1 (intensity 20.5) 34.9869 KeV
Kβ2 (intensity 6.3) 35.8152 KeV
Kβ3 (intensity 8.8) 34.9121 KeV
Lα1 (intensity 100) 4.2865 KeV
Lα2 (intensity 10) 4.2722 KeV
Lβ1 (intensity 49) 4.6198 KeV
Lβ2 (intensity 17) 4.9359 KeV
Lβ3 (intensity 9) 4.7167 KeV
Lβ4 (intensity 4) 4.6488 KeV
Lγ1 (intensity 6) 5.2804 KeV
Lγ2 (intensity 3.5) 5.5462 KeV
Lγ3 (intensity 2) 4.14 KeV
Ll (intensity 4) 3.7976 KeV
Atomic Radii
Empirical 260 pm
Bohr Radius 298 pm
Covalent Radius 225 pm
Van der Waals No data.
Triple covalent No data.
Metallic 265 pm
Oxidation States
Main Cs-1, Cs+1
Other
Ionisation Energies (kJ mol-1) show graph
M - M+ 375.7
M+ - M2+ 2420
M2+ - M3+ 3400
M3+ - M4+ 4400
M4+ - M5+ 6000
M5+ - M6+ 7100
M6+ - M7+ 8300
M7+ - M8+ 11300
M8+ - M9+ 12700
M9+ - M10+ 23700
Vapour Pressure
P (Pa) 1 10 100 1K 10K 100K
T (K) 418 469 534 623 750 940
Crystal Structure
Structure Body centred cubic
a = 614.1 pm
b = 614.1 pm
c = 614.1 pm
α = 90°
β = 90°
γ = 90°