Per Teodor CleveDied 18 Jun 1905 at age 65 (born 10 Feb 1840).Swedish chemist and geologist who who discovered the elements holmium and thulium. He was the thirteenth child in his family. In 1874, Cleve concluded that didymium was in fact two elements (this was proved in 1885 and the two elements named neodymium and praseodymium.) In 1879, he showed that scandium (discovered by Lars Nilson), was in fact the eka-boron predicted by Dmitri Mendeleev in his periodic table. Also in 1879, working with a sample of erbia that had all traces of scandia and ytterbia removed, he found two new earths, which he named holmium, after Stockholm, and thulium, after the old name for Scandinavia. (Holmium, too was a mixture. In 1886, Lecoq de Boisbaudran discovered that it contained the new element dysprosium.) |
