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Francium
Electron Configuration 2,8,18,32,18,8,1
Electron Configuration [Rn] 7s1
Ground state 2S1/2
Atomic Volume g/cm3
Electronegativity 0.7
Magnetic ordering No data
Thermal Properties
Enthalpy of Atomization 71 kJ mol-1 @25°C
Enthalpy of Fusion No data.
Enthalpy of Vaporisation No data.
Heat Capacity ? 15 J mol-1 K-1
Thermal Conductivity No data.
Thermal Expansion No data.
Electrical Properties
Electrical resistivity No data.
Electrical conductivity No data.
Chemical Properties
Electrochemical Equivalent 8.3209 g Ah-1
Valence Electron Potential (-eV) 8
Ionization Potential  
First 3.83
Energy Levels
Kα1 (intensity 0) 86.1 KeV
Kα2 (intensity 0) 83.23 KeV
Kβ1 (intensity 0) 97.47 KeV
Lα1 (intensity 100) 12.0313 KeV
Lα2 (intensity 10) 11.895 KeV
Lβ1 (intensity 38) 14.77 KeV
Lβ2 (intensity 14) 14.45 KeV
Lβ3 (intensity 2) 14.9733 KeV
Lβ4 (intensity 2) 14.3159 KeV
Lγ1 (intensity 8) 17.303 KeV
Lγ2 (intensity 2.7) 17.6268 KeV
Lγ3 (intensity 2) 13.256 KeV
Ll (intensity 6) 10.3801 KeV
Atomic Radii
Empirical 260 pm
Bohr Radius No data.
Covalent Radius No data.
Van der Waals No data.
Triple covalent No data.
Metallic No data.
Ionic Radii (Å)
Charge Coordination Crystal Ionic Key
VI 1.94 1.8 A
R, From r3 vs V plots.
C, Calculated from bond length - bond strength equations.
E, Estimated.
*, Most Reliable.
M, From Metallic Oxides.
A, Ahrens (1952) Ionic radius.
P, Pauling's (1960) Crystal Radius.
Oxidation States
Main Fr+1
Other
Ionisation Energies (kJ mol-1) show graph
M - M+ 400
M+ - M2+ 2100
M2+ - M3+ 3100
M3+ - M4+ 4100
M4+ - M5+ 5700
M5+ - M6+ 6900
M6+ - M7+ 8100
M7+ - M8+ 12300
M8+ - M9+ 12800
M9+ - M10+ 29300
Vapour Pressure
P (Pa) 1 10 100 1K 10K 100K
T (K) 404 454 519 608 738 946