| Cobalt | |
| Electrons per shell | 2,8,15,2 |
| Electron Configuration | [Ar] 3d7 4s2 ![]() |
| Ground state | 4F9/2 |
| Atomic Volume | 6.7 cm3 mol-1 |
| Electronegativity | 1.88 |
| Magnetic ordering | Ferromagnetic |
| Speed of sound | 4720 m s-1 |
Thermal Properties |
|
| Enthalpy of Atomization | 26.8 kJ mol-1 @25°C |
| Enthalpy of Fusion | 15.2 kJ mol-1 |
| Enthalpy of Vaporisation | 382.4 kJ mol-1 |
| Heat Capacity | 24.81 J mol-1 K-1 |
| Thermal Conductivity | 100 W m-1 K-1 |
| Thermal Expansion | 13 μm m-1 K-1 |
| Critcal Temperature | No data. |
| Critcal Pressure | No data. |
| Adiabatic index | No data. |
Hardness |
|
| Brinell hardness | 700 MPa |
| Mohs hardness | 5.0 |
| Vickers hardness | 1043 MPa |
Elastic Properties |
|
| Bulk modulus | 180 GPa |
| Poisson ratio | 0.31 |
| Shear modulus | 75 GPa |
| Young's modulus | 209 GPa |
Electrical Properties |
|
| Electrical resistivity | 6 Ω m |
| Electrical conductivity | 0.172 106/cm Ω |
Chemical Properties |
|
| Electrochemical Equivalent | 1.0994 g Ah-1 |
| Electron Work Function | 5 eV |
| Valence Electron Potential (-eV) | 38.7 |
| Ionization Potential | |
| 7.86 | |
| 17.06 | |
| 33.5 | |
| Incompatibilities | Strong oxidizers, ammonium nitrate (NH4NO3). |
Flammability |
|
Energy Levels |
|
| 6.93032 KeV | |
| 6.9153 KeV | |
| 7.64943 KeV | |
| 0.7762 KeV | |
| 0.7762 KeV | |
| 0.7914 KeV | |
| 0.866 KeV | |
| 0.866 KeV | |
| 0.694 KeV | |
| 0.6773 KeV | |
Atomic Radii |
|
| 135 pm | |
| 152 pm | |
| 126 pm | |
| No data. | |
| 96 pm | |
| 125 pm | |
Ionic Radii (Å) |
||||
| Charge | Coordination | Crystal | Ionic | Key |
| 2 | IV (High spin) | 0.72 | 0.58 | |
| V | 0.81 | 0.67 | C | |
| VI (High spin) | 0.885 | 0.745 | R* | |
| VI (Low spin) | 0.79 | 0.65 | R | |
| VIII | 1.04 | 0.9 | ||
| 3 | VI (High spin) | 0.75 | 0.61 | |
| VI (Low spin) | 0.685 | 0.545 | R* | |
| 4 | IV | 0.54 | 0.4 | |
| VI (High spin) | 0.67 | 0.53 | R | |
| 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 |
|
| Co+2 | |
| Co-1, Co0, Co+1, Co+3, Co+4, Co+5 | |
Ionisation Energies (kJ mol-1) ![]() |
|
| 760 | |
| 1646 | |
| 3232 | |
| 4950 | |
| 7670 | |
| 9840 | |
| 12400 | |
| 15100 | |
| 17900 | |
| 26600 | |
Vapour Pressure |
||||||
| P (Pa) | 1 | 10 | 100 | 1K | 10K | 100K |
| T (K) | 1790 | 1960 | 2165 | 2423 | 2755 | 3198 |
Crystal Structure |
|
| Hexagonal close packed | |
![]() |
a = 250.71 pm |
| b = 250.71 pm | |
| c = 406.95 pm | |
| α = 90° | |
| β = 90° | |
| γ = 120° | |