Isotopes of flerovium

Flerovium (₁₁₄Fl) is a synthetic element, and thus a standard atomic weight cannot be given. Like all synthetic elements, it has no stable isotopes. The first isotope to be synthesized was ²⁸⁹Fl in 1999 (or possibly 1998). Flerovium has six known isotopes, along with the unconfirmed ²⁹⁰Fl, and possibly two nuclear isomers. The longest-lived isotope is ²⁸⁹Fl with a half-life of 1.9 seconds, but ²⁹⁰Fl may have a longer half-life of 19 seconds.