Thulium (Tm): Properties, Uses and Facts in 3D
Thulium is element 69 on the periodic table, a lanthanide, so it is a metal. At room temperature it is a solid. Open it in the 3D Periodic Table to spin its tile, see its electron shells and read its story.
Explore in 3DThulium quick facts
| Atomic number | 69 |
|---|---|
| Symbol | Tm |
| Atomic mass | 168.934 |
| Category | Lanthanide |
| Series and period | Lanthanides, period 6 |
| Block | f-block |
| State at room temperature | Solid |
| Electron configuration | [Xe] 4f¹³ 6s² |
| Electrons per shell | 2, 8, 18, 31, 8, 2 |
| Discovered | 1879, Cleve |
What is thulium used for?
- Portable X-ray devices (Tm-170 source)
- Thulium YAG lasers
- High-temperature superconductor research
Interesting facts about thulium
- Named after Thule. The ancient name for Scandinavia or a mythical northern land
- Thulium-170 emits X-rays. Used in portable X-ray machines not requiring electricity
- Thulium is the rarest of the lanthanides that occur naturally
Thulium was discovered in 1879 by Cleve in Sweden.
Where thulium sits on the periodic table
Thulium is in the lanthanide series (period 6). Tap any element to open its page.
Other lanthanides
Thulium questions
What is the atomic number of thulium?
Thulium has atomic number 69, so every thulium atom has 69 protons in its nucleus. Its symbol is Tm and its atomic mass is 168.934.
Is thulium a metal?
Thulium is a metal. On the periodic table it is grouped as a lanthanide, found in the lanthanide series (period 6).
What is the electron configuration of thulium?
The electron configuration of thulium is [Xe] 4f¹³ 6s². Its electrons sit in 6 shells: 2, 8, 18, 31, 8, 2.
What is thulium used for?
Thulium is used for portable x-ray devices (tm-170 source), thulium yag lasers and high-temperature superconductor research.
Who discovered thulium?
Thulium was discovered in 1879 by Cleve in Sweden.
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