Atomic Radii
Atomic Radius
Bohr Radius
Covalent Radius
Van der Waals
| Niobium | |
| Electron Configuration | 2,8,18,12,1 |
| Electron Configuration | [Kr] 4d4 5s1 |
| Electronegativity | 1.6 |
| Enthalpy of Fusion | 27.2 kJ mol-1 |
| Enthalpy of Vaporisation | 680.19 kJ mol-1 |
| Heat Capacity | 24.60 J mol-1 K-1 |
| Thermal Conductivity | 53.7 W m-1 K-1 |
| Thermal Expansion | 7.3 μm m-1 K-1 |
| Magnetic ordering | No data |
| Electrical resistivity | 152 Ω m |
| Speed of sound | 3480 m s-1 |
| Young's modulus | 105 GPa |
| Shear modulus | 3480 GPa |
| Bulk modulus | 170 GPa |
| Poisson ratio | 0.40 |
| Mohs hardness | 6.0 |
| Vickers hardness | 1320 MPa |
| Brinell hardness | 736 MPa |
| Atomic Radii |
|
| Atomic Radius
|
145 pm |
| Bohr Radius
|
198 pm |
| Covalent Radius
|
137 pm |
| Van der Waals
|
0 pm |
| Oxidation States |
|
| Main
|
Nb+5 |
| Other
|
Nb-3, Nb-1, Nb+1, Nb+2, Nb+3, Nb+4 |
Ionisation Energies (kJ mol-1)  |
|
| M - M+ |
664 |
| M+ - M2+ |
1382 |
| M2+ - M3+ |
2416 |
| M3+ - M4+ |
3695 |
| M4+ - M5+ |
4877 |
| M5+ - M6+ |
9899 |
| M6+ - M7+ |
12100 |