Thulium
☢️ In Your World
Thulium is the second-least abundant of the lanthanides, after the radioactive promethium. Because of its rarity and high cost, it has few commercial applications. Its most notable use is in portable X-ray devices. When bombarded with neutrons in a nuclear reactor, thulium produces an isotope that emits X-rays, creating a lightweight, portable source of radiation for medical diagnostics in the field.
📖 The Discovery Story
Thulium was discovered in 1879 by Swedish chemist Per Teodor Cleve, the same scientist who discovered holmium. He was working with the mineral erbia and meticulously separating out the different rare earth elements it contained. He named the new element "thulium" after Thule, the ancient Greek name for a mythical, distant land in the far north, likely Scandinavia.
📊 Properties at a Glance
| Phase at STP | Solid |
| Melting Point | 1545 °C / 2813 °F |
| Boiling Point | 1950 °C / 3542 °F |
| Electron Configuration | [Xe] 4f¹³6s² |
| Abundance in Earth's Crust | 0.000052% |
⚠️ Safety & Handling
Thulium is a soft, malleable metal that is relatively stable in air. Like other lanthanides, it is considered to have a low level of toxicity. Its dust is a fire and explosion hazard and should be handled with care.