Discovery of thulium

Thulium was discovered in 1879 by the Swedish chemist Per Teodor Cleve at Uppsala University. While investigating the oxide erbia, he found that it contained two other substances, one of which he named holmia and the other thulia, from which the new element took its name. The name refers to Thule, the ancient Greek and Roman name for the northernmost inhabitable land, often identified with Scandinavia. The pure metal was not prepared until 1911. Thulium is the least abundant of the rare earth elements, apart from the radioactive promethium, but it is more common in the Earth's crust than gold or silver. It is a silvery, soft metal that is used in some lasers and in portable X-ray devices, where a radioactive isotope serves as the radiation source.

Open on the timeline