All practice pages/Interatomic theory/Elements
Element 69, a lanthanide
Named for the mythical far north, it is one of the rarest of all the rare earth elements.
Period 6, in the lanthanide row set below the main table. The other lanthanides are tinted, and every cell opens its own article.
Like the other lanthanides, it gives up three electrons to form the Tm³⁺ ion in most of its compounds.
Found in small amounts in monazite, xenotime and ion-adsorption clays.
Per Teodor Cleve found it in 1879 in erbium oxide and named it after Thule, an ancient name for a far northern land, often taken to mean Scandinavia.
Thulium-170 powers portable X-ray devices, thulium lasers are used in surgery, and thulium is studied for superconductors and phosphors. Its rarity and cost keep its uses few.