In 1939, French radiochemist Marguerite Perey discovered francium, the last naturally occurring element to be found, in 1939 while working as a lab technician. She didn’t have a college degree at the time, so, despite having the thesis of a lifetime, she had to return to college to take undergraduate courses before the Sorbonne would let her enroll in its PhD program. She successfully earned a PhD as well as election as a corresponding member of the French Academy of Sciences, making her the first woman ever elected to a French academy.
Perey was born near Paris, France in 1909. Her father died when she was young and her mother couldn’t afford to send her to college, so she interviewed for, and received a job as a chemistry laboratory technician to none other than Marie Curie, at Curie’s Radium Institute.
Marie Curie took on a mentoring role to Perey, taking her on as her personal assistant and teaching her how to isolate and purify radioactive elements, focusing on the chemical element actinium (discovered in Curie's laboratory in 1899 by chemist André-Louis Debierne). Marie Curie died of aplastic anemia only five years after Perey began working with her, but Perey and Debierne continued their research on actinium and Perey was promoted to radiochemist.
In 1935, Perey read a paper by American scientists claiming to have discovered a type of radiation called beta particles being emitted by actinium and was skeptical because the reported energy of the beta particles didn't seem to match actinium. She decided to investigate for herself, theorizing that actinium was decaying into another element (a daughter atom) and that the observed beta particles were actually coming from that daughter atom. She confirmed this by isolating extremely pure actinium and studying its radiation very quickly; she detected a small amount of alpha radiation, a type of radiation that involves the loss of protons and therefore changes an atom's identity. Loss of an alpha particle (consisting of 2 protons and 2 neutrons) would turn actinium (element 89, with 89 protons) into the theorized but never-before-seen element 87. Perey named the element francium, after her home country, and it joined the other alkali metals in Group 1 of the periodic table of elements.
Perey received a grant to study at Paris' Sorbonne, but because she didn't have a bachelor's degree, the Sorbonne required her to take courses and obtain the equivalent of a B.S. to fulfill their Ph.D. program requirements before she could earn her doctorate. She graduated from the Sorbonne in 1946 with a Doctorate of Physics and returned to the Radium Institute as a senior scientist, working there until 1949.
She then joined the University of Strasbourg in 1949 as Chair of Nuclear Chemistry. She developed the University's radiochemistry and nuclear chemistry program and founded and led a laboratory that in 1958 became the Laboratory of Nuclear Chemistry in the Center for Nuclear Research. She continued her work on francium. She found it accumulated in tumors in mice and hoped that it might be used to diagnose cancer.
In 1962, Perey was elected to the French Academy of Sciences in 1962, making her the first woman elected to the Institut de France. Although a significant step, her election as a "corresponding member" rather than a full member came with limited privileges.
Years of work with radioactivity took their toll and Perey died from bone cancer in 1975, though she is credited with having championed the use of stricter safety measures for work with radioactive materials.
Photo: Musée Curie/ACJC Collection