Isotopes of flerovium
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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 seven known isotopes, and possibly 2 nuclear isomers. The longest-lived isotope is 289Fl with a half-life of 1.9 seconds, but the unconfirmed 290Fl may have a longer half-life of 19 seconds.
The below table contains various combinations of targets and projectiles which could be used to form compound nuclei with an atomic number of 114.
This section deals with the synthesis of nuclei of flerovium by so-called "cold" fusion reactions. These are processes which create compound nuclei at low excitation energy (~10–20 MeV, hence "cold"), leading to a higher probability of survival from fission. The excited nucleus then decays to the ground state via the emission of one or two neutrons only.
The first attempt to synthesise flerovium in cold fusion reactions was performed at Grand accélérateur national d'ions lourds (GANIL), France in 2003. No atoms were detected providing a yield limit of 1.2 pb. The team at RIKEN have indicated plans to study this reaction.
This section deals with the synthesis of nuclei of flerovium by so-called "hot" fusion reactions. These are processes which create compound nuclei at high excitation energy (~40–50 MeV, hence "hot"), leading to a reduced probability of survival from fission. The excited nucleus then decays to the ground state via the emission of 3–5 neutrons. Fusion reactions utilizing 48Ca nuclei usually produce compound nuclei with intermediate excitation energies (~30–35 MeV) and are sometimes referred to as "warm" fusion reactions. This leads, in part, to relatively high yields from these reactions.
The first experiments on the synthesis of flerovium were performed by the team in Dubna in November 1998. They were able to detect a single, long decay chain, assigned to 289
Fl. The reaction was repeated in 1999 and a further two atoms of flerovium were detected. The products were assigned to 288
Fl. The team further studied the reaction in 2002. During the measurement of the 3n, 4n, and 5n neutron evaporation excitation functions they were able to detect three atoms of 289
Fl, twelve atoms of the new isotope 288
Fl, and one atom of the new isotope 287Fl. Based on these results, the first atom to be detected was tentatively reassigned to 290
Fl or 289mFl, whilst the two subsequent atoms were reassigned to 289
Fl and therefore belong to the unofficial discovery experiment. In an attempt to study the chemistry of copernicium as the isotope 285
Cn, this reaction was repeated in April 2007. Surprisingly, a PSI-FLNR directly detected two atoms of 288
Fl forming the basis for the first chemical studies of flerovium.
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