Marguerite Perey
French physicist and chemist who discovered francium, the last natural element.
Marguerite Catherine Perey (19 October 1909 – 13 May 1975) was a French physicist and a protégée of Marie Curie. Born in Villemomble near Paris, she initially hoped to study medicine, but her father’s death left her family in financial difficulty. In 1929, she earned a chemistry diploma from the Paris Technical School of Women’s Education, which qualified her as a technician. That same year, at age nineteen, she was hired as Marie Curie’s personal assistant at the Radium Institute. Under Curie’s mentorship, Perey learned to isolate and purify radioactive elements, focusing on actinium. After Curie’s death, Perey and chemist André-Louis Debierne continued this work, and she was promoted to radiochemist.
In 1935, Perey read a paper claiming that actinium emitted beta particles, but she doubted the reported energy levels. Investigating, she theorized that actinium was decaying into a daughter element, which was the true source of the radiation. By isolating extremely pure actinium and quickly studying its emissions, she detected alpha radiation—a loss of protons that would transform actinium (element 89) into the undiscovered element 87. On 9 January 1939, her discovery was announced to the Académie des Sciences by Jean Baptiste Perrin, as Perey lacked a university degree. She named the element francium after France. Francium is the second rarest naturally occurring element, with only about 550 grams present in Earth’s crust at any time, and it was the last element discovered in nature.
Perey later received a grant to study at the Sorbonne, but lacking a bachelor’s degree, she had to earn the equivalent before pursuing a PhD. She graduated in 1946 with a Doctorate of Physics; her thesis covered francium. Afterward, she returned to the Radium Institute as a senior scientist until 1949, when she became head of nuclear chemistry at the University of Strasbourg. There she built a radiochemistry program and founded a laboratory that became the Laboratory of Nuclear Chemistry in the Center for Nuclear Research, serving as its director. She also served on the Atomic Weights Commission from 1950 to 1963 and was nominated five times for a Nobel Prize, though she never won. Francium proved carcinogenic rather than therapeutic; Perey developed bone cancer from her work and died in 1975. She is credited with advocating for better radiation safety. In 1962, she became the
- field
- Physics, radiochemistry
- nationality
- French
- known_for
- Discovery of francium (element 87)
Lore & Background
Although she hoped to study medicine, her father's death left the family in financial difficulties. Under Curie's guidance, Perey learned to isolate and purify radioactive elements, focusing on actinium. She theorized actinium was decaying into another element and detected alpha radiation, which indicated a loss of protons. This led to her discovery of element 87, which she named francium. She founded a laboratory that became the Laboratory of Nuclear Chemistry. Perey was nominated five times for a Nobel Prize but never received it. She is credited with championing better safety measures for scientists working with radiation.
Reader's Guide
Her work was carried out under challenging circumstances: she lacked a university degree at the time of discovery and had to rely on a male colleague to present her findings to the Académie des Sciences. Perey's career also advanced nuclear chemistry education and research at the University of Strasbourg, where she built a laboratory and directed the Center for Nuclear Research. Though she hoped francium might help diagnose cancer, its carcinogenicity ultimately contributed to her own death. Perey's story highlights the barriers faced by women in science and the persistence required to overcome them.
Did You Know?
- Francium is the rarest naturally occurring element, with only about 20-30 grams existing in Earth's crust at any given time.
- Perey was the first woman elected to the French Académie des Sciences, an honor denied to her mentor Marie Curie.
- She was nominated five times for a Nobel Prize but never received it.
Frequently Asked Questions
What field of science did Marguerite Perey specialize in?
Perey worked in radiochemistry and nuclear physics, concentrating on the behavior and purification of radioactive isotopes. It was precisely this laboratory work on actinium that led to her landmark discovery.
More in Chemists And Biochemists 1-24
Spotted an error? Know more?
This is a living reference — every entry is fact-audited, and reader corrections feed straight into our audit queue. Suggest an edit · See this site's audit record