Swedish chemist and geologist · 1840–1905
Per Teodor Cleve
Per Teodor Cleve found two rare-earth elements in a single year, holmium and thulium in 1879, and showed that Nilson’s new element scandium was the one Mendeleev had predicted.
- Elements credited
- 2
- Discoveries
- 1878–1879
- Co-discoverers
- 2
- Where
- Switzerland and Sweden; Sweden
The work
After Marignac separated ytterbium from erbia, Cleve examined what was left and found it still showed foreign spectral lines. He separated two new earths. One he named holmia, after Holmia, the Latin name for Stockholm. The other he named thulia, after Thule, the ancient name for the far north.
Delafontaine and Soret in Geneva had seen holmium’s spectrum the year before, calling it “element X”, so the credit is shared. Cleve was the first to isolate it chemically.
Holmium and Thulium side by side
Life and career
Cleve was born in Stockholm and spent his career at Uppsala University, where he became professor of chemistry. One of his students was Svante Arrhenius, who later won the Nobel Prize.
Later in life he studied diatoms, microscopic algae, and used them to trace ocean currents and the history of the Baltic Sea. His daughter Astrid Cleve became the first Swedish woman to earn a doctorate in science.
Also known for
- Classification of diatoms and plankton research
- Showed scandium matched Mendeleev’s eka-boron