| Tantalum | |
| Electrons per shell | 2,8,18,32,11,2 |
| Electron Configuration | [Xe] 4f14 5d3 6s2 ![]() |
| Ground state | 4F3/2 |
| Atomic Volume | 10.9 cm3 mol-1 |
| Electronegativity | 1.5 |
| Magnetic ordering | No data |
| Mass magnetic susceptibility | 1.07 x 10-8 |
| Molar magnetic susceptibility | 1.936 x 10-9 |
| Speed of sound | 3400 m s-1 |
Thermal Properties |
|
| Enthalpy of Atomization | 782 kJ mol-1 @25°C |
| Enthalpy of Fusion | 31.4 kJ mol-1 |
| Enthalpy of Vaporisation | 758.2 kJ mol-1 |
| Heat Capacity | 25.36 J mol-1 K-1 |
| Thermal Conductivity | 57.5 W m-1 K-1 |
| Thermal Expansion | 6.3 μm m-1 K-1 |
| Critcal Temperature | No data. |
| Critcal Pressure | No data. |
| Adiabatic index | No data. |
Hardness |
|
| Brinell hardness | 800 MPa |
| Mohs hardness | 6.5 |
| Vickers hardness | 873 MPa |
Elastic Properties |
|
| Bulk modulus | 200 GPa |
| Poisson ratio | 0.34 |
| Shear modulus | 69 GPa |
| Young's modulus | 186 GPa |
Electrical Properties |
|
| Electrical resistivity | 1.3 x 10-7 Ω m |
| Electrical conductivity | 0.0761 106/cm Ω |
Chemical Properties |
|
| Electrochemical Equivalent | 1.3502 g Ah-1 |
| Electron Work Function | 4.25 eV |
| Valence Electron Potential (-eV) | 110 |
| Ionization Potential | |
| 7.89 | |
| Incompatibilities | Strong oxidizers, bromine trifluoride (BrF3), fluorine. |
Flammability |
|
Energy Levels |
|
| 57.532 KeV | |
| 56.277 KeV | |
| 65.223 KeV | |
| 66.289 KeV | |
| 65.1134 KeV | |
| 8.1461 KeV | |
| 8.0879 KeV | |
| 9.3431 KeV | |
| 9.6518 KeV | |
| 9.4846 KeV | |
| 9.2108 KeV | |
| 10.8952 KeV | |
| 11.2151 KeV | |
| 8.426 KeV | |
| 7.17 KeV | |
Atomic Radii |
|
| 145 pm | |
| 200 pm | |
| 138 pm | |
| No data. | |
| 119 pm | |
| 146 pm | |
Ionic Radii (Å) |
||||
| Charge | Coordination | Crystal | Ionic | Key |
| 3 | VI | 0.86 | 0.72 | E |
| 4 | VI | 0.82 | 0.68 | E |
| 5 | VI | 0.78 | 0.64 | |
| VII | 0.83 | 0.69 | ||
| 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 |
|
| Ta+5 | |
| Ta-3, Ta-1, Ta+1, Ta+2, Ta+3, Ta+6 | |
Ionisation Energies (kJ mol-1) ![]() |
|
| 761 | |
| 1500 | |
| 2100 | |
| 3200 | |
| 4300 | |
Covalent Bonds (kJ mol-1) |
|
Vapour Pressure |
||||||
| P (Pa) | 1 | 10 | 100 | 1K | 10K | 100K |
| T (K) | 3297 | 3597 | 3957 | 4395 | 4939 | 5634 |
Crystal Structure |
|
| Body centred cubic | |
![]() |
a = 330.13 pm |
| b = 330.13 pm | |
| c = 330.13 pm | |
| α = 90° | |
| β = 90° | |
| γ = 90° | |