| Niobium | |
| Electrons per shell | 2,8,18,12,1 |
| Electron Configuration | [Kr] 4d4 5s1 ![]() |
| Ground state | |
| Atomic Volume | 10.87 cm3 mol-1 |
| Electronegativity | 1.6 |
| Magnetic ordering | No data |
| Mass magnetic susceptibility | 2.81 x 10-8 |
| Molar magnetic susceptibility | 2.611 x 10-9 |
| Speed of sound | 3480 m s-1 |
Thermal Properties |
|
| Enthalpy of Atomization | 745 kJ mol-1 @25°C |
| 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 |
| Critcal Temperature | No data. |
| Critcal Pressure | No data. |
| Adiabatic index | No data. |
Hardness |
|
| Brinell hardness | 736 MPa |
| Mohs hardness | 6.0 |
| Vickers hardness | 1320 MPa |
Elastic Properties |
|
| Bulk modulus | 170 GPa |
| Poisson ratio | 0.40 |
| Shear modulus | 38 GPa |
| Young's modulus | 105 GPa |
Electrical Properties |
|
| Electrical resistivity | 1.5 x 10-7 Ω m |
| Electrical conductivity | 0.0693 106/cm Ω |
Chemical Properties |
|
| Electrochemical Equivalent | 0.69327 g Ah-1 |
| Electron Work Function | 4.3 eV |
| Valence Electron Potential (-eV) | 104 |
| Ionization Potential | |
| 6.88 | |
| 14.32 | |
| 25.04 | |
Energy Levels |
|
| 16.6151 KeV | |
| 16.521 KeV | |
| 18.6225 KeV | |
| 18.9497 KeV | |
| 18.6044 KeV | |
| 2.16589 KeV | |
| 2.163 KeV | |
| 2.2574 KeV | |
| 2.367 KeV | |
| 2.3347 KeV | |
| 2.3198 KeV | |
| 2.4618 KeV | |
| 1.996 KeV | |
| 1.9001 KeV | |
Atomic Radii |
|
| 145 pm | |
| 198 pm | |
| 137 pm | |
| No data. | |
| 116 pm | |
| 146 pm | |
Ionic Radii (Å) |
||||
| Charge | Coordination | Crystal | Ionic | Key |
| 3 | VI | 0.86 | 0.72 | |
| 4 | VI | 0.82 | 0.68 | RE |
| VIII | 0.93 | 0.79 | ||
| 5 | IV | 0.62 | 0.48 | C |
| VI | 0.78 | 0.64 | ||
| VII | 0.83 | 0.69 | C | |
| VIII | 0.88 | 0.74 | ||
| 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 |
|
| Nb+5 | |
| Nb-3, Nb-1, Nb+1, Nb+2, Nb+3, Nb+4 | |
Ionisation Energies (kJ mol-1) ![]() |
|
| 664 | |
| 1382 | |
| 2416 | |
| 3695 | |
| 4877 | |
| 9899 | |
| 12100 | |
Vapour Pressure |
||||||
| P (Pa) | 1 | 10 | 100 | 1K | 10K | 100K |
| T (K) | 2949 | 3207 | 3524 | 3910 | 4393 | 5013 |
Crystal Structure |
|
| Body centred cubic | |
![]() |
a = 330.04 pm |
| b = 330.04 pm | |
| c = 330.04 pm | |
| α = 90° | |
| β = 90° | |
| γ = 90° | |