Sinonimi: Fr | atomic number 87
Radioactive metallic element, symbol Fr, atomic number 87, atomic weight 223. It is one of the alkali metals and occurs in nature in small amounts as a decay product of actinium. Its longest-lived isotope has a half-life of only 21 minutes. Francium was discovered and named in 1939 by Marguérite Perey to honor her country.
A radioactive element of the alkali-metal group discovered as a disintegration product of actinium; SYN. Fr, atomic number 87.