Isotopes of Francium

Isotopes Of Francium

Francium (Fr) has no stable isotopes. A standard atomic mass cannot be given. Its most stable isotope is 223Fr with a half-life of 22 minutes, occurring in trace quantities as an intermediate decay product of 235U. The other natural isotope is 221Fr.

Of elements whose most stable isotopes have been identified with certainty, Francium is the most unstable. All elements with atomic number of greater than or equal to 106 (Seaborgium) have most-stable-known isotopes shorter than that of Francium, but those elements have only a relatively small number of isotopes discovered, thus, there is the possibility of a yet-unknown isotope having a longer half-life.