Dysprosium (Dy)

The name means "hard to get at", which Lecoq de Boisbaudran chose after more than thirty attempts at separating it. A neodymium magnet loses strength as it heats, and an electric car motor runs hot, so a few percent of dysprosium is added to hold the coercivity — that single requirement makes dysprosium one of the most supply-critical elements in the energy transition. It also has one of the highest magnetic strengths of any element at low temperature, second only to holmium.

Properties

Atomic number

66

Symbol

Dy

Standard atomic weight

162.5 u

Category

Lanthanide

Period

6

Block

f-block

Electron configuration

[Xe] 6s² 4f¹⁰

Electrons per shell

2, 8, 18, 28, 8, 2

Melting point

1,685 K — 1411.8 °C — 2573.3 °F

Boiling point

2,840 K — 2566.8 °C — 4652.3 °F

Density

8.55 g/cm³

Electronegativity

1.22 (Pauling)

Oxidation states

+3

Discovered

1886 by Paul-Émile Lecoq de Boisbaudran

Electron configuration

Full

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁰

Noble gas shorthand

[Xe] 6s² 4f¹⁰

Shells

K: 2 · L: 8 · M: 18 · N: 28 · O: 8 · P: 2

What it is used for

• Keeping neodymium magnets working at electric-motor temperatures
• Terfenol-D actuators and sonar transducers
• Dysprosium-doped control rods in reactors
• Dosimeters, where dysprosium-doped crystals store radiation dose

Neighbours in the table