March 21, 1946 - Marguerite Perey submits her thesis on ‘L'élément 87: Actinium K’, known as Francium

On January 7, 1939, Marguerite Perey observed an anomalous radiation in actinium that she attributed to a new element, 87, which had the properties corresponding to an alkaline and which she would initially call Actinium K. She had just discovered the last remaining natural element. to complete Mendeleev's periodic table of 92 elements.

The members of the Paris Institute of Radium, where he worked first as Marie Curie's laboratory assistant and later as a radiochemist, thought that he would present it as his doctoral thesis, just as Marie had done with radium. The problem wasn't just that Marguerite didn't have a college degree, it's that she didn't even have a bachelor's degree. At her Institute they decided to remove her from all laboratory tasks and got her a scholarship so that she could study at the Sorbonne. She attended medical school to gain access to an advanced degree and then modules in chemistry, biology, and physiology that the university deemed equivalent to a bachelor's degree (Marguerite's case was exceptional in every way).

Finally, on March 21, 1946, at the age of 36, Marguerite presented her thesis on “L’élément 87: Actinium K”. The last sentence of it collected the privilege of the discoverer: "The name Francio, Fa, is proposed for place 87" (today the symbol of francio is Fr).

She did not win a Nobel Prize, but in 1962 she became the first woman to be elected to the Paris Academy of Sciences, something even Marie Curie did not achieve.

If you want to know more about this great scientist, click on the following link: Marguerite-Catherine Perey