Hafnium
Silvery lustrous metallic transition element. Used in tungsten alloys in filaments and electrodes, also acts as a neutron absorber. First reported by Urbain in 1911, existence was finally established in 1923 by D. Coster, G.C. de Hevesy in 1923.
Gallery
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Emission spectrum
Physical Propertiesmass · density · phase · crystal
Atomic Mass
178.4900Da
Density
13.3000g/cm³
Phase (STP)
Solid
Melting Point
2506.2K
Boiling Point
4873.1K
Molar Heat
0.1440J/(mol·K)
Crystal Structure
HEX
Lattice Constant
3.200Å
Atomic Radiiatomic · covalent · van der Waals
Atomic (Empirical)
155.00pm
Covalent
152.00pm
Van der Waals
223.00pm
Electronic Propertieselectronegativity · ionization · affinity
Electron Configuration
[Xe] 4f14 5d2 6s2
Electron Shells
2, 8, 18, 32, 10, 2
Electronegativity
1.30Pauling
Electron Affinity
0.0kJ/mol
1st Ionization Energy
6.8kJ/mol
Oxidation States
+2, +3, +4
Orbital DiagramAufbau · Hund's rule · Pauli exclusion
Full: 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d2 6s2Short: [Xe] 4f14 5d2 6s2
Ionization Energies (72 known)
Emission Spectrumvisible range · characteristic spectral lines
Abundanceby mass
Log scale · ppm = parts per million by mass
Biological Role
No known biological role. Very low toxicity.
Discovery
Discovered By
Dirk Coster, Georg von Hevesy
Named By
—
Year
1923
Nuclear Data
Known Isotopes
38
Stable Isotopes
5
Stable Mass Numbers
176, 177, 178, 179, 180
Natural isotopic abundance (IUPAC recommended values)
Isotopes of Hf38 known
| Nuclide | Z | N | Mass (AMU) | Half-life | Decay | Jπ | Abundance |
|---|---|---|---|---|---|---|---|
| 153Hf | 72 | 81 | 152.970692 | Unknown | β⁺ | 1/2+ | — |
| 154Hf | 72 | 82 | 153.964863 | 2.00 s | β⁺ (1%), α (0%) | 0+ | — |
| 155Hf | 72 | 83 | 154.963167 | 843 ms | β⁺ (1%), α | 7/2- | — |
| 174Hf | 72 | 102 | 173.940048 | 2000000 Gy | α (1%), 2β⁺ | 0+ | 16.0000% |
| 176Hfstable | 72 | 104 | 175.941410 | Stable | stable (1%) | 0+ | 526.0000% |
| 177Hfstable | 72 | 105 | 176.943230 | Stable | stable (1%) | 7/2- | 1860.0000% |
| 178Hfstable | 72 | 106 | 177.943708 | Stable | stable (1%) | 0+ | 2728.0000% |
| 179Hfstable | 72 | 107 | 178.945826 | Stable | stable (1%) | 9/2+ | 1362.0000% |
| 180Hfstable | 72 | 108 | 179.946560 | Stable | stable (1%) | 0+ | 3508.0000% |
| 188Hf | 72 | 116 | 187.966903 | Unknown | β⁻ | 0+ | — |
| 189Hf | 72 | 117 | 188.970853 | Unknown | β⁻ (1%) | 3/2- | — |
| 190Hf | 72 | 118 | 189.973376 | Unknown | β⁻ | 0+ | — |