Ra-224

Francium-221 (Fr-221) is a short-lived radioactive isotope of francium with a half-life of about 4.8 minutes. It decays primarily by alpha emission to astatine-217 and is part of the decay chain associated with uranium-233. Because of its very short half-life, Fr-221 exists only temporarily before decaying into other radionuclides.

Fr-221 has no significant commercial or medical applications because of its short half-life and extremely limited availability. It is mainly of interest in nuclear physics, where it is studied to better understand the properties, structure, and radioactive decay of heavy nuclei.

Fr-221 occurs as a short-lived member of the uranium-233 decay series. It is produced by the alpha decay of actinium-225 and subsequently decays to astatine-217. It can therefore be encountered in materials containing Ac-225 and in specialized nuclear research or isotope-production environments. Because its half-life is only a few minutes, Fr-221 is present only while being continuously produced by its parent isotope.

Fr-221

Francium-221
Technogenic α, γ radiation

Half-life: 4.8 minutes Main emission lines: 100, 218, 410 keV