Per Teodor Cleve
Who was Per Teodor Cleve?
Swedish chemist who discovered holmium and thulium (1840-1905)
Biographical data adapted from Wikipedia’s article on Per Teodor Cleve (CC BY-SA 4.0).
Biography
Per Teodor Cleve was born on February 10, 1840, in Stockholm, Sweden. He became one of the most industrious scientists of the nineteenth century, working in chemistry, biology, mineralogy, and oceanography. He was known for his careful investigations and curiosity across different areas of study. He died on June 18, 1905, in Uppsala. Most of his professional career was spent at Uppsala University, where he also studied.
Cleve got his Bachelor of Science degree from Uppsala University in 1863 and his doctorate there in 1868. After earning his PhD, he joined Uppsala University as an assistant professor of chemistry and eventually became a professor of general and agricultural chemistry. In this role, he did the lab work that made him a notable figure in science. In 1874, he suggested that didymium was not one element but actually two, a theory later proven by Carl Auer von Welsbach in 1885 with the discovery of neodymium and praseodymium. In 1879, five years after making this suggestion, Cleve made his most famous discoveries by isolating the chemical elements holmium and thulium from the mineral erbia. He named holmium after Holmia, the Latin name for Stockholm, his birthplace. His work in chemistry also included finding aminonaphthalenesulfonic acids, known as Cleve's acids, which were important in making synthetic dyes.
Around 1890, Cleve shifted his focus to biological and oceanographic research. He created a new way to figure out the age and order of geological layers from late glacial and postglacial times by studying diatom fossils in them. Diatoms, tiny algae with silica shells that preserve well in sediment, were useful in showing past environmental conditions. Cleve's use of them for geological dating was a significant method. He also wrote a major book on oceanography, helping advance the scientific understanding of ocean biology and plankton distribution.
Cleve was married to Alma Cleve, and their daughter, Astrid Cleve, also became a noted scientist. In 1894, Cleve received the Davy Medal from the Royal Society of London, one of the top awards in chemistry, for his discovery of holmium and thulium. This award showed the high regard the international scientific community had for his work in elemental chemistry. He continued his research nearly until his death, leaving a broad range of studies that impacted future scientists in chemistry, geology, and marine biology.
Before Fame
Per Teodor Cleve grew up in Stockholm at a time when Sweden was modernizing and European science was growing quickly with more investment in universities and labs. The mid-1800s saw a lot of elemental discoveries, with chemists using new techniques to identify substances that older methods couldn't. Uppsala University, one of the oldest and most respected in Scandinavia, gave Cleve a strong scientific education and a place that supported his wide range of interests.
After finishing his doctorate in 1868, Cleve took on an academic role with access to well-equipped labs and a community of dedicated scholars. His early work focused on inorganic chemistry and analyzing rare earth minerals, a hot topic as researchers thought known substances might hide undiscovered elements. This careful and persistent work laid the foundation for the discoveries that later brought him international recognition.
Key Achievements
- Discovery of the chemical elements holmium and thulium in 1879
- Early prediction that didymium was composed of two distinct elements, later confirmed as neodymium and praseodymium
- Discovery of aminonaphthalenesulfonic acids, known as Cleve's acids, important in synthetic dye chemistry
- Development of a diatom-based method for dating late glacial and postglacial geological deposits
- Awarded the Davy Medal by the Royal Society in 1894 for contributions to elemental chemistry
Did You Know?
- 01.Cleve named the element holmium after Holmia, the Latinized form of Stockholm, the city where he was born.
- 02.His daughter Astrid Cleve became a distinguished scientist in her own right, working in chemistry and geology.
- 03.Cleve predicted as early as 1874 that didymium was two elements, but had to wait over a decade for another scientist to confirm the theory experimentally.
- 04.He used the microscopic silica shells of diatoms as a tool for dating ancient geological deposits, pioneering a method that would influence later paleoecological research.
- 05.The aminonaphthalenesulfonic acids he discovered bear his name as Cleve's acids and were significant in the industrial chemistry of synthetic dyes.
Family & Personal Life
Awards & Honors
| Award | Year | Details |
|---|---|---|
| Davy Medal | 1894 | — |