Periodic Table Logo
Tb

Terbium

Atomic number: 65Mass: 158.925 uCategory: Lanthanide

About Terbium

Terbium is a silvery-white, rare earth metal that is malleable, ductile, and soft enough to be cut with a knife. It is used in green phosphors and in making magnetostrictive alloys that change shape in magnetic fields.

Properties

Period
6
Group
N/A
Block
F
Category
Lanthanide
Electronegativity
1.10 (Pauling)
Ionization Energy
565.8 kJ/mol
Melting Point
1629 K (1356°C)
Boiling Point
3503 K (3230°C)
Density
8.23 g/cm³
Oxidation States
+3, +4

Electron Configuration

1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f⁹ 5s² 5p⁶ 6s²
[Xe] 4f⁹ 6s²
Shell 1:2e⁻
Shell 2:8e⁻
Shell 3:18e⁻
Shell 4:27e⁻
Shell 5:8e⁻
Shell 6:2e⁻

Real-World Uses

Green phosphors (displays)
Sonar devices (Terfenol-D)
Solid-state drives
Fuel cells
Medicine

Fun Fact

Terbium makes sonar equipment more sensitive — alloys containing terbium expand and contract with magnetic fields, creating sound waves!