|
|
| Tantalum | |
| Electron Configuration | 2,8,18,32,11,2 |
| Electron Configuration | [Xe] 4f14 5d3 6s2 |
| Ground state | 4F3/2 |
| Atomic Volume | 10.9 g/cm3 |
| 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 |
| 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 | No data. |
| Chemical Properties |
|
| Electrochemical Equivalent | 1.3502 g Ah-1 |
| Electron Work Function | 4.25 eV |
| Valence Electron Potential (-eV) | 110 |
| Ionization Potential | |
 First
|
7.89 |
| Incompatibilities | Strong oxidizers, bromine trifluoride (BrF3), fluorine. |
| Flammability |
|
| Combustible Solid, fine dust is easily ignited
|
| Energy Levels |
|
| Kα1 (intensity 100) |
57.532 KeV |
| Kα2 (intensity 50) |
56.277 KeV |
| Kβ1 (intensity 25.3) |
65.223 KeV |
| Kβ2 (intensity 9.9) |
66.289 KeV |
| Kβ3 (intensity 9.9) |
65.1134 KeV |
| Lα1 (intensity 100) |
8.1461 KeV |
| Lα2 (intensity 10) |
8.0879 KeV |
| Lβ1 (intensity 42) |
9.3431 KeV |
| Lβ2 (intensity 20) |
9.6518 KeV |
| Lβ3 (intensity 6.7) |
9.4846 KeV |
| Lβ4 (intensity 4) |
9.2108 KeV |
| Lγ1 (intensity 8.2) |
10.8952 KeV |
| Lγ2 (intensity 2) |
11.2151 KeV |
| Lγ3 (intensity 2) |
8.426 KeV |
| Ll (intensity 4.5) |
7.17 KeV |
| Atomic Radii |
|
| Empirical
|
145 pm |
| Bohr Radius
|
200 pm |
| Covalent Radius
|
138 pm |
| Van der Waals
|
No data. |
| Triple covalent
|
119 pm |
| Metallic
|
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 |
|
| Main
|
Ta+5 |
| Other
|
Ta-3, Ta-1, Ta+1, Ta+2, Ta+3, Ta+6 |
Ionisation Energies (kJ mol-1)  |
|
| M - M+ |
761 |
| M+ - M2+ |
1500 |
| M2+ - M3+ |
2100 |
| M3+ - M4+ |
3200 |
| M4+ - M5+ |
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 |
|
| Structure
|
Body centred cubic |
 |
a = 330.13 pm |
| b = 330.13 pm | |
| c = 330.13 pm | |
| α = 90° | |
| β = 90° | |
| γ = 90° | |