|
|
| Chromium | |
| Electron Configuration | 2,8,13,1 |
| Electron Configuration | [Ar] 3d5 4s1 |
| Ground state | 7S3 |
| Atomic Volume | 7.23 g/cm3 |
| 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 | No data. |
| 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 |
| Ionic Radii (Å) |
||||
| Charge | Coordination | Crystal | Ionic | Key |
| 2 | VI (High spin) | 0.94 | 0.8 | R* |
| VI (Low spin) | 0.87 | 0.73 | E | |
| 3 | VI | 0.755 | 0.615 | R* |
| 4 | IV | 0.55 | 0.41 | |
| VI | 0.69 | 0.55 | R | |
| 5 | IV | 0.485 | 0.345 | R |
| VI | 0.63 | 0.49 | ER | |
| VIII | 0.71 | 0.57 | ||
| 6 | IV | 0.4 | 0.26 | |
| VI | 0.58 | 0.44 | C | |
| 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
|
Cr+3 |
| Other
|
Cr-2, Cr-1, Cr0, Cr+1, Cr+2, Cr+4, Cr+5, Cr+6 |
Ionisation Energies (kJ mol-1)  |
|
| 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° | |