|
|
| Hafnium | |
| Electron Configuration | 2,8,18,32,10,2 |
| Electron Configuration | [Xe] 4f14 5d2 6s2 |
| Ground state | 3F2 |
| Atomic Volume | 13.6 g/cm3 |
| Electronegativity | 1.3 |
| Magnetic ordering | No data |
| Mass magnetic susceptibility | 5.3 x 10-9 |
| Molar magnetic susceptibility | 9.46 x 10-10 |
| Speed of sound | 3010 m s-1 |
 Thermal Properties |
|
| Enthalpy of Atomization | 703 kJ mol-1 @25°C |
| Enthalpy of Fusion | 25.5 kJ mol-1 |
| Enthalpy of Vaporisation | 570.7 kJ mol-1 |
| Heat Capacity | 25.73 J mol-1 K-1 |
| Thermal Conductivity | 23.0 W m-1 K-1 |
| Thermal Expansion | 5.9 μm m-1 K-1 |
| Hardness |
|
| Brinell hardness | 1700 MPa |
| Mohs hardness | 5.5 |
| Vickers hardness | 1760 MPa |
| Elastic Properties |
|
| Bulk modulus | 110 GPa |
| Poisson ratio | 0.37 |
| Shear modulus | 30 GPa |
| Young's modulus | 78 GPa |
| Electrical Properties |
|
| Electrical resistivity | 3.0 x 10-7 Ω m |
| Electrical conductivity | No data. |
| Chemical Properties |
|
| Electrochemical Equivalent | 1.6649 g Ah-1 |
| Electron Work Function | 3.9 eV |
| Valence Electron Potential (-eV) | 81 |
| Ionization Potential | |
 First
|
6.65 |
| Second
|
14.925 |
| Third
|
23.32 |
| Incompatibilities | Strong oxidizers, chlorine. |
| Flammability |
|
| Explosive in powder form
|
| Energy Levels |
|
| Kα1 (intensity 100) |
55.7902 KeV |
| Kα2 (intensity 50) |
54.6114 KeV |
| Kβ1 (intensity 25.1) |
63.234 KeV |
| Kβ2 (intensity 9.7) |
64.3746 KeV |
| Kβ3 (intensity 9.9) |
63.109 KeV |
| Lα1 (intensity 100) |
7.899 KeV |
| Lα2 (intensity 10) |
7.8446 KeV |
| Lβ1 (intensity 44) |
9.0227 KeV |
| Lβ2 (intensity 19) |
9.3473 KeV |
| Lβ3 (intensity 8) |
9.1599 KeV |
| Lβ4 (intensity 4) |
8.9039 KeV |
| Lγ1 (intensity 7.5) |
10.5158 KeV |
| Lγ2 (intensity 4) |
10.8324 KeV |
| Lγ3 (intensity 2) |
8.137 KeV |
| Ll (intensity 5.5) |
6.9583 KeV |
| Atomic Radii |
|
| Empirical
|
155 pm |
| Bohr Radius
|
208 pm |
| Covalent Radius
|
150 pm |
| Van der Waals
|
No data. |
| Triple covalent
|
122 pm |
| Metallic
|
159 pm |
| Ionic Radii (Å) |
||||
| Charge | Coordination | Crystal | Ionic | Key |
| 4 | IV | 0.72 | 0.58 | R |
| VI | 0.85 | 0.71 | R | |
| VII | 0.9 | 0.76 | ||
| VIII | 0.97 | 0.83 | ||
| 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
|
Hf+4 |
| Other
|
Hf+1, Hf+2, Hf+3 |
Ionisation Energies (kJ mol-1)  |
|
| M - M+ |
642 |
| M+ - M2+ |
1440 |
| M2+ - M3+ |
2250 |
| M3+ - M4+ |
3216 |
| Vapour Pressure |
||||||
| P (Pa) | 1 | 10 | 100 | 1K | 10K | 100K |
| T (K) | 2689 | 2954 | 3277 | 3679 | 4194 | 4876 |
| Crystal Structure |
|
| Structure
|
Hexagonal close packed |
 |
a = 319.64 pm |
| b = 319.64 pm | |
| c = 505.11 pm | |
| α = 90° | |
| β = 90° | |
| γ = 120° | |