Kawéntenan kacawang olih Dmitri Mendeleev warsa 1869, yadiastun nénten kauningin nganti warsa 1923, olih Coster miwah Hevesy, manadosang nyané datu stabil ungkur kalih sané katemuin.
In 1869, the existence of this element was predicted by Dmitri Mendeleev, even though it was not previously identified by Coster and Hevesy until 1923, making it the last stable element to be discovered.