About

Hafnium is a lustrous, silvery-gray transition metal. It is chemically very similar to zirconium and is found in the same minerals, making it difficult to separate. Its excellent ability to absorb neutrons makes it ideal for use in control rods in nuclear submarines and power plants, where it regulates the fission process. It is also used in microprocessors and alloys.

Atomic Properties

Atomic Number72

Atomic Weight178.49 u

Neutrons (common)108

Electron Configuration[Xe] 4f¹⁴ 5d² 6s²

Full Configuration1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d² 6s²

Electrons per Shell2, 8, 18, 32, 10, 2

Electronegativity1.3

Oxidation States+4, +3, +2

Covalent Radius155 pm

Ionic Radius71 pm

Periodic Table Position

Group4

Period6

BlockD

Chemical SeriesTransition metals

Physical Properties

State at STPsolid

AppearanceLustrous, silvery, ductile metal

Crystal Structurehcp

Magnetic Orderingparamagnetic

Speed of Sound3,010 m/s

Poisson Ratio0.37

Thermal Properties

Melting Point2,506 K

Boiling Point4,876 K

Thermal Expansion0 1/K

Thermal Conductivity23 W/(m·K)

Specific Heat0.144 J/(g·K)

Molar Heat25.7 J/(mol·K)

Heat of Fusion27.2 kJ/mol

Heat of Vaporization630 kJ/mol

Abundance

In Earth's Crust3.3 ppm

In Ocean0 ppm

In Solar System0 ppm

In Universe0.001 ppm

Discovery

Discovered byDirk Coster, George de Hevesy

Discovery Year1,923

Occurrenceprimordial

CAS Number7440-58-6

Electron Configuration

Energy

↿⇂

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Isotopes of Hafnium

Symbol ▲	Mass (u) ▲	Abundance ▲	Half-life ▲	Decay Mode ▲
¹⁷⁴Hf	173.940040	0.16%	2.0 Py	Alpha Decay
¹⁷⁶Hf	175.941400	5.26%	Stable	Stable
¹⁷⁷Hf	176.943220	18.6%	Stable	Stable
¹⁷⁸Hf	177.943700	27.28%	Stable	Stable
¹⁷⁹Hf	178.945810	13.62%	Stable	Stable
¹⁸⁰Hf	179.946550	35.08%	Stable	Stable

Interactive Visualization

Explore the 3D Bohr model of Hafnium in our interactive viewer.

View 3D Model of Hafnium