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Chlorine
Electron Configuration 2,8,7
Electron Configuration [Ne] 3s2 3p5
Ground state 23/2
Atomic Volume 22.7 g/cm3
Electronegativity 3.16
Magnetic ordering Non-magnetic
Mass magnetic susceptibility -7.2 x 10-9
Molar magnetic susceptibility -2.55 x 10-10
Speed of sound 206 m s-1
Thermal Properties
Enthalpy of Atomization 121.8 kJ mol-1 @25°C
Enthalpy of Fusion 6.41 kJ mol-1
Enthalpy of Vaporisation 20.403 kJ mol-1
Heat Capacity (Cl2) 33.949 J mol-1 K-1
Thermal Conductivity 8.9 W m-1 K-1
Thermal Expansion No data.
Electrical Properties
Electrical resistivity 10+ Ω m
Electrical conductivity No data.
Chemical Properties
Electrochemical Equivalent 1.3228 g Ah-1
Valence Electron Potential (-eV) -7.96
Ionization Potential  
First 12.967
Second 23.81
Third 39.611
Incompatibilities Reacts explosively or forms explosive compounds with many common substances such as acetylene (C2H2), ether, turpentine, ammonia (NH3), fuel gas, hydrogen and finely divided metals.
Flammability
Non-flammable gas (strong oxidizer)
Optical Properties
Refractive Index (gas) 1.000773
Energy Levels
Kα1 (intensity 100) 2.62239 KeV
Kα2 (intensity 0) 2.62078 KeV
Kβ1 (intensity 8.9) 2.8156 KeV
Lα1 (intensity 100) 0.1827 KeV
Lγ3 (intensity 0) 0.184 KeV
Ll (intensity 100) 0.1827 KeV
Atomic Radii
Empirical 100 pm
Bohr Radius 79 pm
Covalent Radius 99 pm
Van der Waals 175 pm
Triple covalent 93 pm
Metallic No data.
Ionic Radii (Å)
Charge Coordination Crystal Ionic Key
-1  VI 1.67 1.81 P
IIIPY 0.26 0.12
IV 0.22 0.08 *
VI 0.41 0.27 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 Cl-1, Cl+7
Other Cl+1, Cl+3, Cl+4, Cl+5, Cl+6
Ionisation Energies (kJ mol-1) show graph
M - M+ 1251.1
M+ - M2+ 2297
M2+ - M3+ 3826
M3+ - M4+ 5158
M4+ - M5+ 6540
M5+ - M6+ 9362
M6+ - M7+ 11020
M7+ - M8+ 33610
M8+ - M9+ 38600
M9+ - M10+ 43960
Covalent Bonds (kJ mol-1)
Cl-O 206
Cl-Cl 242
Cl-F 257
Cl-H 431
Vapour Pressure
P (Pa) 1 10 100 1K 10K 100K
T (K) 128 139 153 170 197 239
Crystal Structure
Structure Orthorhombic
a = 622.35 pm
b = 445.61 pm
c = 817.85 pm
α = 90°
β = 90°
γ = 90°