Hafnium (Hf)
Transition metal · d-block · period 6 · group 4
Lustrous, silvery, ductile metal.
Hafnium (symbol Hf) is chemical element number 72, a transition metal in group 4, period 6 of the periodic table. Its standard atomic weight is 178.49 and its electron configuration is [Xe] 4f14 5d2 6s2. At room temperature it is a solid. Named after Hafnia, the Latin name for Copenhagen.
Properties
| Atomic number | 72 |
|---|---|
| Atomic mass | 178.49 |
| Category | Transition metal |
| Block | d-block |
| Group · Period | 4 · 6 |
| Electron configuration | [Xe] 4f14 5d2 6s2 |
| Electrons per shell | 2, 8, 18, 32, 10, 2 |
| State at 25 °C | solid |
| Melting point | 2506 K |
| Boiling point | 4876 K |
| Density | 13.31 g/cm³ |
| Electronegativity (Pauling) | 1.3 |
| Radioactive | No |
| Origin | primordial |
| Discovered | 1922 · Coster & Hevesy |
Key facts about Hafnium
- Named after Hafnia, the Latin name for Copenhagen.
- Chemically almost a twin of zirconium and very hard to separate from it.
- Absorbs neutrons superbly, so it makes submarine-reactor control rods.
- A hafnium compound is used as the insulating layer in modern computer chips.
What Hafnium is used for
Nuclear reactor control rods, chip insulators, superalloys for rocket nozzles, plasma cutting electrodes.
Where it sits in the periodic table
Hafnium is in group 4, period 6, of the d-block. Its electron configuration [Xe] 4f14 5d2 6s2 means its outermost shell holds 2 electrons, which is what places it here and explains much of its chemistry. See Hafnium on the interactive table →
Hafnium — frequently asked questions
What is Hafnium used for?
Nuclear reactor control rods, chip insulators, superalloys for rocket nozzles, plasma cutting electrodes.
Is Hafnium radioactive?
No. Hafnium has at least one stable isotope and is not radioactive.
What is the electron configuration of Hafnium?
Hafnium has the electron configuration [Xe] 4f14 5d2 6s2, which is 2, 8, 18, 32, 10, 2 electrons per shell.
What group and period is Hafnium in?
Hafnium is in group 4, period 6, in the d-block. Its outer shell holds 2 electrons.
Who discovered Hafnium?
Hafnium was discovered in 1922 by Coster & Hevesy.