Francium

Francium is a naturally occurring element–a highly radioactive alkali metal with one valence electron. At any given moment there is 20-30 grams of Francium (about an ounce) present on Earth. This tiny sample is found in the form of individual atoms located within uranium and thorium ores around the Earth’s crust.   The half-life of the longest-lived isotope of francium is only 22 minutes. The weird transient metal continuously vanishes (decaying into astatine, radium, or radon)–only to be continuously replaced when actinium-227 decays into francium-223.

Marguerite Catherine Perey (19 October 1909 – 13 May 1975), French physicist

How did we ever even find out about this stuff if it only exists as 20 grams of individual atoms scattered around the entire world like evanescent Easter eggs? I’m glad you asked! It was discovered by a French woman in 1939. Marguerite Catherine Perey (1909 – 1975) was born in 1909 in Villemomble, France (just outside Paris)–where Marie Curie’s Radium Institute also happened to be located. Perey aspired to be a medical doctor, but her family fell into financial difficulty so, at the age of 19, she took a job at a local spot–working directly for Marie Curie. Curie died of exotic cancer in 1934, but Perey kept up her mentor’s work purifying and studying actinium and looking for a theorized “eka-caesium” (a heretofore unknown alkali metal with an atomic number of 87). Through her methodic and painstaking work and observations, Perey discovered it just as World War II. broke out. Francium was the last element discovered in nature. The rest have been synthesized in labs.

Marguerite Perey (second from left) at the Curie laboratory in 1930

After discovering an entirely new atom, Perey finally received a grant to pursue her university studies, and she received her PhD from the Sorbonne in 1946. In 1960 she became an officer of the Legion of Honor. She founded the laboratory which ultimately grew into became the Laboratory of Nuclear Chemistry in the Center for Nuclear Research and she was the first woman to be elected to the French Académie des Sciences.

True to her original dream of helping people as a doctor, Perey hoped that francium would help diagnose cancer and make the disease more treatable, but sadly, francium itself was carcinogenic (which is something to remember, if you find an atom of it sitting in some uranium ore). In her late life, Perey developed bone cancer which eventually killed her–a dark fruit of her pioneering research.

I mention francium this week, not because of its name (coincidentally, it is named after the great nation of France), but because of the life of the scientist who discovered it. Marguerite Catherine Perey had to struggle against prejudice and steroetypes, but she was able to overcome them and move to the foremost ranks of scientists and leaders of France. Her research helped that country become a nuclear leader (which it still is) and helped humankind better understand the nature of chemistry and physics.

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