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Atomic: M.A.C. | Reference
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Chromium
Electrons per shell 2,8,13,1
Electron Configuration [Ar] 3d5 4s1 open electron config
Ground state 7S3
Atomic Volume 7.23 cm3 mol-1
Electronegativity 1.66
Magnetic ordering Antiferromagnetic
Mass magnetic susceptibility 4.45 x 10-8
Molar magnetic susceptibility 2.314 x 10-9
Speed of sound 5940 m s-1
Thermal Properties
Enthalpy of Atomization 121.8 kJ mol-1 @25°C
Enthalpy of Fusion 15.3 kJ mol-1
Enthalpy of Vaporisation 341.8 kJ mol-1
Heat Capacity 23.35 J mol-1 K-1
Thermal Conductivity 93.9 W m-1 K-1
Thermal Expansion 4.9 μm m-1 K-1
Hardness
Brinell hardness 1120 MPa
Mohs hardness 8.5
Vickers hardness 1060 MPa
Elastic Properties
Bulk modulus 160 GPa
Poisson ratio 0.21
Shear modulus 115 GPa
Young's modulus 279 GPa
Electrical Properties
Electrical resistivity 1.27 x 10-7 Ω m
Electrical conductivity 0.0774 106/cm Ω
Chemical Properties
Electrochemical Equivalent 0.32333 g Ah-1
Electron Work Function 4.5 eV
Valence Electron Potential (-eV) 170
Ionization Potential  
First 6.766
Second 16.5
Third 30.96
Incompatibilities Strong oxidizers (such as hydrogen peroxide (H2O2), alkalis.
Flammability
Non-combustible solid (except as dust)
Energy Levels
Kα1 (intensity 100) 5.41472 KeV
Kα2 (intensity 50) 5.405509 KeV
Kβ1 (intensity 20) 5.94671 KeV
Lα1 (intensity 100) 0.5728 KeV
Lα2 (intensity 10) 0.5728 KeV
Lβ1 (intensity 19.3) 0.5828 KeV
Lβ3 (intensity 0.5) 0.654 KeV
Lβ4 (intensity 0.5) 0.654 KeV
Lγ3 (intensity 22) 0.51 KeV
Ll (intensity 78) 0.5 KeV
Atomic Radii
Empirical 140 pm
Bohr Radius 166 pm
Covalent Radius 127 pm
Van der Waals No data.
Triple covalent 103 pm
Metallic 128 pm
Oxidation States
Main Cr+3
Other Cr-2, Cr-1, Cr0, Cr+1, Cr+2, Cr+4, Cr+5, Cr+6
Ionisation Energies (kJ mol-1) show graph
M - M+ 652.7
M+ - M2+ 1592
M2+ - M3+ 2987
M3+ - M4+ 4740
M4+ - M5+ 6690
M5+ - M6+ 8738
M6+ - M7+ 15550
M7+ - M8+ 17830
M8+ - M9+ 20220
M9+ - M10+ 23580
Vapour Pressure
P (Pa) 1 10 100 1K 10K 100K
T (K) 1656 1807 1991 2223 2530 2942
Crystal Structure
Structure Body centred cubic
a = 291 pm
b = 291 pm
c = 291 pm
α = 90°
β = 90°
γ = 90°