francium-223

Francium-223 is an isotope of francium (Fr), the heaviest chemical element in Group 1 of the periodic table, also known as an alkali metal. Francium is a highly radioactive element with only short-lived forms, and it cannot be isolated in visible amounts. Francium-223 is the longest-lived isotope of francium, with a half-life of only 22 minutes. It occurs naturally as a decay product of actinium. While 34 other isotopes of francium have been artificially created, francium-223 is the most stable. The chemistry of francium is studied using methods for trace quantities, and its behavior is consistent with that of an alkali element.12