Terbium (Tb)
Lanthanide · f-block · period 6
Silvery-grey, soft, ductile rare-earth metal.
Terbium (symbol Tb) is chemical element number 65, a lanthanide in the lanthanide series (f-block), period 6 of the periodic table. Its standard atomic weight is 158.93 and its electron configuration is [Xe] 4f9 6s2. At room temperature it is a solid. Named, like yttrium and erbium, after the village of Ytterby in Sweden.
Properties
| Atomic number | 65 |
|---|---|
| Atomic mass | 158.93 |
| Category | Lanthanide |
| Block | f-block |
| Group · Period | f-block series · 6 |
| Electron configuration | [Xe] 4f9 6s2 |
| Electrons per shell | 2, 8, 18, 27, 8, 2 |
| State at 25 °C | solid |
| Melting point | 1629 K |
| Boiling point | 3396 K |
| Density | 8.23 g/cm³ |
| Electronegativity (Pauling) | 1.2 |
| Radioactive | No |
| Origin | primordial |
| Discovered | 1843 · Carl Gustaf Mosander |
Key facts about Terbium
- Named, like yttrium and erbium, after the village of Ytterby in Sweden.
- Provides the green glow in fluorescent lamps and older TV tubes.
- An alloy called Terfenol-D changes shape in a magnetic field, used in precise actuators and sonar.
- One of the scarcest and priciest of the rare earths.
What Terbium is used for
Green phosphors for lighting and displays, magnetostrictive actuators and sonar, solid-state devices, fuel cells.
Where it sits in the periodic table
Terbium is in the lanthanide series, period 6, of the f-block. Its electron configuration [Xe] 4f9 6s2 means its outermost shell holds 2 electrons, which is what places it here and explains much of its chemistry. See Terbium on the interactive table →
Terbium — frequently asked questions
What is Terbium used for?
Green phosphors for lighting and displays, magnetostrictive actuators and sonar, solid-state devices, fuel cells.
Is Terbium radioactive?
No. Terbium has at least one stable isotope and is not radioactive.
What is the electron configuration of Terbium?
Terbium has the electron configuration [Xe] 4f9 6s2, which is 2, 8, 18, 27, 8, 2 electrons per shell.
What group and period is Terbium in?
Terbium is in the lanthanide series (f-block), period 6, in the f-block. Its outer shell holds 2 electrons.
Who discovered Terbium?
Terbium was discovered in 1843 by Carl Gustaf Mosander.