About

Holmium is a bright, soft, silvery rare-earth metal. It possesses the highest magnetic strength of any element, which allows it to be used to create the pole pieces of the strongest static magnets, concentrating magnetic flux. Its compounds are used to color glass and cubic zirconia yellow or red, and it is a key component in some solid-state lasers.

Atomic Properties

Atomic Number67

Atomic Weight164.93 u

Neutrons (common)98

Electron Configuration[Xe] 4f¹¹ 6s²

Full Configuration1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹¹ 5s² 5p⁶ 6s²

Electrons per Shell2, 8, 18, 29, 8, 2

Electronegativity1.23

Electron Affinity32.61 kJ/mol

Oxidation States+3

Covalent Radius158 pm

Van der Waals Radius226 pm

Ionic Radius90.1 pm

Periodic Table Position

Group3

Period6

BlockF

Chemical SeriesLanthanoids

Physical Properties

State at STPsolid

Appearancesilvery white

Crystal Structurehcp

Magnetic Orderingparamagnetic

Speed of Sound2,760 m/s

Poisson Ratio0.231

Thermal Properties

Melting Point1,734 K

Boiling Point2,993 K

Triple Point1,734 K

Thermal Expansion0 1/K

Thermal Conductivity16.2 W/(m·K)

Specific Heat0.165 J/(g·K)

Molar Heat27.21 J/(mol·K)

Heat of Fusion17 kJ/mol

Heat of Vaporization271 kJ/mol

Abundance

In Earth's Crust1.3 ppm

In Ocean0 ppm

In Solar System0 ppm

In Universe0.001 ppm

Discovery

Discovered byJacques-Louis Soret, Marc Delafontaine, Per Teodor Cleve

Discovery Year1,878

Occurrenceprimordial

CAS Number7440-60-0

Electron Configuration

Energy

↿⇂

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Isotopes of Holmium

Symbol ▲	Mass (u) ▲	Abundance ▲	Half-life ▲	Decay Mode ▲
¹⁶³Ho	162.928726	—	4570 y	Electron Capture
¹⁶⁵Ho	164.930320	100%	Stable	Stable

Interactive Visualization

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

View 3D Model of Holmium