Hf
178.490Hafnium
Hafniyum
Hafnium is a group 4 transition metal with atomic number 72. It is known for hafnium oxide high-k dielectrics in microchips, neutron-absorbing control rods, zirconium similarity and ultra-high-temperature hafnium compounds.
72
178.49 g/mol
[Xe] 4f¹⁴ 5d² 6s²
2 | 8 | 18 | 32 | 10 | 2
1.3
13.31 g/cm³
2232.8 °C
4602.9 °C
Dirk Coster
Hafnium was discovered in 1923 by Dirk Coster and George de Hevesy in Copenhagen using X-ray spectroscopy of zirconium minerals. Its name comes from Hafnia, the Latin name for Copenhagen.
Hafnium-174
Natural abundance: About 0.16%. Rare natural hafnium isotope.Hafnium-176
Natural abundance: About 5.3%. Stable isotope and daughter product in Lu-Hf dating.Hafnium-177
Natural abundance: About 18.6%. Stable isotope of hafnium.Hafnium-178
Natural abundance: About 27.3%. Stable isotope; the Hf-178m2 isomer is a separate excited nuclear state.Hafnium-179
Natural abundance: About 13.6%. Stable isotope of hafnium.Hafnium-180
Natural abundance: About 35.1%. Most abundant natural hafnium isotope.HfO₂
Hafnium DioxideHigh-k dielectric material used in advanced semiconductor gate stacks.HfCl₄
Hafnium(IV) ChloridePrecursor for hafnium oxide thin films and hafnium chemistry.HfC
Hafnium CarbideUltra-high-temperature ceramic for extreme thermal environments.HfN
Hafnium NitrideHard, refractory coating and high-temperature material.- Hafnium oxide high-k gate dielectrics in modern microchips and transistors
- Nuclear reactor control rods because hafnium absorbs neutrons strongly
- Hafnium carbide and nitride ultra-high-temperature ceramics
- Plasma cutting and welding electrodes
- Specialty alloys and polymerization catalyst systems
Hafnium has no known essential biological role. It is mainly important as a nuclear and electronic material, with exposure concerns limited to industrial compounds and dusts.
- Hafnium and zirconium are extremely difficult to separate because lanthanide contraction makes their ionic radii very similar.
- HfO₂ helped semiconductor technology move beyond very thin SiO₂ gate layers by reducing leakage current.
- Hafnium absorbs neutrons strongly, while zirconium is valued in fuel cladding because it absorbs neutrons weakly.
- The element name honors Copenhagen, where the element was discovered.
- Hafnium has atomic number 72 and is a group 4 transition metal.
- Its electron configuration is [Xe] 4f¹⁴ 5d² 6s².
- The common oxidation state is +4.
- Remember HfO₂ for high-k dielectrics and hafnium metal for neutron control rods.
What is the atomic number of hafnium?
The atomic number of hafnium is 72.
What is the electron configuration of hafnium?
Hafnium has the electron configuration [Xe] 4f¹⁴ 5d² 6s².
What is hafnium used for?
Hafnium is used in high-k dielectrics, reactor control rods, refractory ceramics, plasma electrodes and specialty catalysts.
Why is hafnium oxide important in microchips?
Hafnium oxide has a high dielectric constant, allowing thicker gate insulators with lower leakage than very thin silicon dioxide layers.
Why is hafnium used in nuclear control rods?
Hafnium has a strong ability to absorb neutrons, which helps regulate fission in nuclear reactors.
Why are hafnium and zirconium hard to separate?
They have very similar chemistry and ionic sizes because lanthanide contraction makes hafnium closely resemble zirconium.