66 Dy 162.5

Dysprosium

Lanthanide Dysprosium solid

[Xe] 4f¹⁰ 6s² · 2 · 8 · 18 · 28 · 8 · 2

← Tb Terbium Ho Holmium →

The lanthanide with the strongest magnetic moment of any element at low temperature, and an indispensable additive in electric vehicle magnets: without dysprosium they weaken as they heat.

3D model

Bohr model: nucleus and electron shells from the real configuration. Valence electrons are highlighted.

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Atomic properties

Atomic number: 66
Atomic mass: 162.5 а.е.м.
Electron configuration: [Xe] 4f¹⁰ 6s²
Electrons per shell: 2 · 8 · 18 · 28 · 8 · 2
Block: f-block
Group: no data
Period: 6
Electronegativity (Pauling): 1.22
Electronegativity (Allen): 1.1
Atomic radius: 229 pm
Covalent radius: 192 pm
Van der Waals radius: 229 pm
Ionisation energy 1: 573 kJ/mol
Ionisation energy 2: 1 130 kJ/mol
Ionisation energy 3: 2 200 kJ/mol
Ionisation energy 4: 3 990 kJ/mol
Electron affinity: 50 kJ/mol
Common oxidation states: +3
Oxidation states: +2, +3, +4

Physical properties

State at 25 °C: solid
Density: 8.54 g/cm³
Melting point: 1 680 K · 1 406.9 °C
Boiling point: 2 840 K · 2 566.9 °C
Speed of sound: 2 710 m/s

Thermal properties

Heat of fusion: 11.06 kJ/mol
Heat of vaporisation: 280 kJ/mol
Specific heat capacity: 0.17 J/(g·K)
Thermal conductivity: 10.7 W/(m·K)

Mechanical properties

Young's modulus: 61.4 GPa
Shear modulus: 24.7 GPa
Bulk modulus: 40.5 GPa
Poisson ratio: 0.25
Mohs hardness: no data
Brinell hardness: 500 MPa

Electrical and magnetic properties

Electrical resistivity: 926 nΩ·m
Magnetic ordering: paramagnetic
Curie point: 85 K
Néel point: no data
Superconducting point: no data

Crystal structure

Crystal structure: hexagonal close-packed (hcp)
Lattice constants: a = 359.15 pm · c = 565.01 pm

Abundance

In the crust: 5.2 mg/kg
In the ocean: 9·10⁻⁷ mg/L
In the universe: 0.2 mg/kg
In the human body: no data

Isotopes

Isotope	Abundance	Half-life	Decay mode
¹⁵⁶Dy	0.056 %	stable	—
¹⁵⁸Dy	0.095 %	stable	—
¹⁶⁰Dy	2.329 %	stable	—
¹⁶¹Dy	18.889 %	stable	—
¹⁶²Dy	25.475 %	stable	—
¹⁶³Dy	24.896 %	stable	—
¹⁶⁴Dy	28.26 %	stable	—

Seven stable isotopes. Dysprosium-165 is used in radiosynovectomy of joints.

Discovery

Year of discovery: 1886
Discovered by: Paul-Émile Lecoq de Boisbaudran
Where: France
Origin of the name: from Greek dysprositos (hard to get at): it was very hard to isolate

History

Lecoq de Boisbaudran isolated dysprosium in 1886 after more than thirty successive precipitations. The name is from the Greek for hard to get at.

Where it occurs

5.2 mg/kg of the crust. The principal source is the ion-adsorption clays of southern China.

How it is produced

By ion exchange and solvent extraction of heavy rare earths. Dysprosium is classed as a critical raw material for the energy transition.

Role in living things

No biological role.

Safety

Of low toxicity. Dust and powder are a fire hazard, and soluble salts mildly irritate skin and mucous membranes.

Uses

An additive in Nd-Fe-B magnets, holding coercivity at 150–200 °C
Terfenol-D, alongside terbium
Nuclear reactor control rods
Dosimetry: dysprosium in thermoluminescent dosimeters

Curiosities

The name means hard to get at, from the extraordinary difficulty of isolating it.
Dysprosium is a bottleneck for electric motors: without it a car magnet weakens on a hot engine.
Below 85 K dysprosium becomes ferromagnetic.
Dysprosium and holmium have the highest magnetic moments of any elements.