Per Teodor Cleve

Lore & Background

Per Teodor Cleve was a chemist at Uppsala University. His daughter, Astrid Cleve, was the first Swedish woman to obtain a doctoral degree of science. She married Hans von Euler-Chelpin, who won the Nobel Prize in Chemistry in 1929 with Arthur Harden for their investigations on the fermentation of sugar and enzymes. Euler-Chelpin was a professor of general and organic chemistry at Stockholm University (1906–1941) and director of its Institute for organic-chemical research (1938–1948). The couple had five children: Sten (1903–1991), Ulf Svante (1905–1983), Karin Maria (1907–2003), Hans Georg Rigas (1908–2003) and Birgit (1910–2000).

Reader's Guide

Per Teodor Cleve’s scientific work spanned chemistry, biology, mineralogy, and oceanography, with his most celebrated achievement being the discovery of the elements holmium and thulium in 1879. He identified holmium while purifying erbium oxide, isolating a brown substance that proved to be holmium oxide, and separately obtained thulium oxide as a green substance from the same source. Earlier, in 1874, Cleve theorized that the substance known as didymium was actually a mixture of two elements, a prediction confirmed in 1885 when neodymium and praseodymium were discovered. He also isolated scandium in 1879, confirming it as the predicted element eka-boron, and, with Abraham Langlet, discovered helium in the mineral cleveite in 1895. In organic chemistry, Cleve synthesized aminonaphthalenesulfonic acids, later called Cleve’s acids, and prepared numerous complex platinum compounds, observing isomerism in platinumamine derivatives for the first time. After 1890, he shifted focus to biology, studying freshwater algae, diatoms, and plankton. He developed a method for dating late glacial and postglacial deposits by analyzing diatom fossils, and wrote a foundational text in oceanography. Cleve’s contributions to chemistry and oceanography established him as a versatile natural scientist, and his work on element discovery and analytical methods remains significant in his fields.

Did You Know?

• Per Teodor Cleve was a chemist at Uppsala University.
• His daughter Astrid Cleve was the first Swedish woman to obtain a doctoral degree of science.
• Astrid Cleve married Hans von Euler-Chelpin, who won the Nobel Prize in Chemistry in 1929.
• Hans von Euler-Chelpin was a professor of general and organic chemistry at Stockholm University from 1906 to 1941.
• Ulf von Euler, grandson of Per Teodor Cleve, won the Nobel Prize in Physiology or Medicine in 1970.

The Uppsala Chemist

Per Teodor Cleve is recorded in historical sources as a chemist at Uppsala, a position that anchored him within the Swedish academic world of the late nineteenth and early twentieth centuries. The available records do not detail the specific subfield he pursued or the particular research questions he addressed, but his professional identity as a practicing chemist at Uppsala was central to how he is remembered. His role in that institution shaped the intellectual environment in which he raised his family, and it provided the disciplinary foundation from which his daughter Astrid would later emerge as a scientist in her own right. The fact that Cleve is preserved in the historical record largely through his connection to his daughter and son-in-law suggests a career that, while respected within its institutional setting, did not attract the same degree of international attention as some of his contemporaries. Nevertheless, his standing as a Uppsala chemist placed him within the broader Scandinavian network of chemical science, a network that would later intersect with the Stockholm-based laboratory work of Hans von Euler-Chelpin, the man who would marry his daughter and go on to win a Nobel Prize.

A Groundbreaking Daughter

Astrid Cleve, daughter of Per Teodor Cleve, achieved a distinction that marked a significant moment for women in Swedish science: she became the first Swedish woman to earn a doctoral degree in the sciences. As a chemist in her own right, she carried forward the academic tradition established by her father at Uppsala while breaking through barriers that had long excluded women from the highest levels of scientific training in Sweden. Her doctoral achievement was not merely a personal milestone but a signal that the Scandinavian academic world was beginning to admit female scholars into the natural sciences at the most advanced level. Astrid's professional identity as a chemist meant she shared a common intellectual language with her father, and their shared discipline likely shaped the household's culture of inquiry and rigorous investigation. Her subsequent marriage to Hans von Euler-Chelpin, a German-born biochemist who would later share the 1929 Nobel Prize in Chemistry with Arthur Harden for their work on sugar fermentation and enzymes, further embedded her within the international scientific community. Together the couple raised five children, continuing the family's deep and sustained involvement in the chemical and biological sciences.

A Scientific Dynasty

The marriage of Astrid Cleve to Hans von Euler-Chelpin created a family unit that became one of the most remarkable scientific lineages in Scandinavian history. Per Teodor Cleve, as Astrid's father, was the foundational figure in this lineage—a Uppsala chemist whose daughter would marry a Stockholm professor of general and organic chemistry. The union produced five children: Sten, Ulf Svante, Karin Maria, Hans Georg Rigas, and Birgit. The family's scientific pedigree was extraordinary: Astrid was the first Swedish woman to hold a science doctorate, her father was a recognized Uppsala chemist, and her husband went on to share the 1929 Nobel Prize in Chemistry with Arthur Harden for their investigations into the fermentation of sugar and the role of enzymes. The household thus combined multiple generations of chemical expertise under one roof in Stockholm. Karin, one of the five children, would later marry the writer Sven Stolpe, introducing a literary dimension into the family's cultural life. This interweaving of chemistry, biochemistry, and letters made the Cleve-Euler-Chelpin family a unique and densely connected node in the intellectual landscape of early twentieth-century Sweden.

Legacy Through the Next Generation

Per Teodor Cleve's most enduring legacy is carried forward through his descendants, particularly through the achievements of his daughter Astrid's children. His grandson Ulf Svante von Euler, born in 1905, became a prominent physiologist who in 1970 was awarded the Nobel Prize in Physiology or Medicine for his research on the chemical nature of norepinephrine at the synapses. This meant that within a single family, two Nobel Prizes were earned across different scientific disciplines—chemistry in 1929 and physiology in 1970—spanning four decades and two generations. The broader family tree also extended into other intellectual territories: Karin married the writer Sven Stolpe and had four children with him, one of whom was Lisette Schulman. The five children of Astrid and Euler-Chelpin—Sten, Ulf, Karin, Hans Georg Rigas, and Birgit—each carried forward the scientific and cultural traditions established by their grandparents. Per Teodor Cleve, the Uppsala chemist, thus stands as the quiet origin point of a family whose contributions touched chemistry, biochemistry, physiology, and literature across three generations of Swedish and international intellectual life.