Hf
Hafnium
Element 72 · Transition metal
Hafnium (Hf)
Hafnium is a lustrous, silvery metal that is almost always found with zirconium. It absorbs neutrons strongly.
- Transition metal
- Period 6
- Group 4
- d-block
- solid at room temperature
Key properties
- Atomic mass
- 178.49
- u
- Electron configuration
- [Xe] 4f14 5d2 6s2
- Melting point
- 2,232.9 °C
- 2,506 K
- Boiling point
- 4,602.9 °C
- 4,876 K
- Density
- 13.3 g/cm³
- Electronegativity
- 1.3
- Pauling
- Atomic radius
- 212 pm
- van der Waals
- 1st ionisation energy
- 6.825 eV
Compare with every element:Electronegativity chartAtomic radius chartIonisation energy chartDensity chart of the elementsMelting point chartElectron configuration chart
Did you know?
Notable facts about hafnium
- 01
It was found by X-ray spectroscopy, guided by Niels Bohr’s prediction of its chemistry.
- 02
Hafnium and zirconium are so chemically alike that separating them is extremely difficult.
- 03
Hafnium oxide insulators made faster, cooler computer chips possible from 2007 onward.
Applications
What is hafnium used for?
- Nuclear control rods
- Microchip gate insulators
- Superalloys for jet engines
- Plasma cutting tips
History
Discovery & name origin
Discovered by
Year
Where
Denmark
Name origin
Latin Hafnia, “Copenhagen”, where it was discovered.
Atomic structure
Atomic properties
Atomic structure
Atomic properties
- Atomic number
- 72
- Atomic mass
- 178.49 u
- Group
- 4
- Period
- 6
- Block
- d-block
- Electron configuration
- [Xe] 4f14 5d2 6s2
- Full configuration
- 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d2
- Electrons per shell
- 2, 8, 18, 32, 10, 2
- Electronegativity (Pauling)
- 1.3
- Electron affinity
- —
- Atomic radius (van der Waals)
- 212 pm
- Stable isotopes
- 5
Oxidation states
Highlighted: common oxidation states (+4).
Successive ionisation energies
Energy to remove each electron in turn (kJ/mol). Big jumps show where a new, inner shell begins.
- 1st658.5
- 2nd1,440
- 3rd2,250
- 4th3,216
Physical
Physical properties & colour
Physical
Physical properties & colour
- State at 20 °C
- Solid
- Melting point
- 2,506 K · 2,232.9 °C · 4,051.1 °F
- Boiling point
- 4,876 K · 4,602.9 °C · 8,317.1 °F
- Density
- 13.3 g/cm³
- Molar heat capacity
- 25.73 J/(mol·K)
- Appearance
- Steel grey
- CPK model colour
- Copied
The CPK colour is the convention used for this element’s atoms in molecular models.
FAQ
Hafnium questions
What is Hf on the periodic table?
Hf is the symbol for hafnium, element 72 on the periodic table. It sits in group 4, period 6, in the transition metal category, and has an atomic mass of 178.49.
What is the atomic number of hafnium?
Hafnium has atomic number 72, so every hafnium atom has 72 protons in its nucleus. Its symbol is Hf and its atomic mass is 178.49.
Who discovered hafnium?
Hafnium was discovered by Dirk Coster and George de Hevesy in 1923 (Denmark). The name comes from Latin Hafnia, “Copenhagen”, where it was discovered.
What is hafnium used for?
Hafnium is used for: nuclear control rods; microchip gate insulators; superalloys for jet engines; plasma cutting tips.
Is hafnium a metal?
Yes. Hafnium is a transition metal, one of the metallic elements.
What is the electron configuration of hafnium?
The electron configuration of hafnium is [Xe] 4f14 5d2 6s2. Its 72 electrons are arranged in shells as 2, 8, 18, 32, 10, 2.