Flerovium is a synthetic, highly radioactive superheavy element in group 14. It has no stable isotopes and only a few atoms have been produced; bulk properties are unknown.
Flerovium (Fl) is a superheavy, synthetic p-block element with atomic number 114 in Group 14 (the carbon–silicon–germanium–tin–lead family). It is named after the Flerov Laboratory of Nuclear Reactions (JINR, Dubna), honoring physicist Georgy Flerov.
Fl lies below lead (Pb) in Group 14. Because of strong relativistic effects that stabilize the 7s electrons and split 7p orbitals, theory predicts unusually weak reactivity and a preference for +2 over +4 in condensed-phase chemistry—i.e., Fl(II) may be more stable than Fl(IV), unlike lighter congeners.
A commonly cited ground state is [Rn] 5f14 6d10 7s2 7p2. Relativistic stabilization of 7s and strong spin–orbit splitting of 7p (\(7p_{1/2}\) vs. \(7p_{3/2}\)) help explain Fl’s predicted inert, quasi-noble behavior and the favoring of the +2 oxidation state.
Fl is made via fusion–evaporation reactions using a calcium-48 beam on a plutonium target; the hot compound nucleus sheds a few neutrons to form Fl isotopes. Stylized examples:
\(^{244}\mathrm{Pu}(^{48}\mathrm{Ca},\,4n)\,^{288}\mathrm{Fl}\)
\(^{244}\mathrm{Pu}(^{48}\mathrm{Ca},\,3n)\,^{289}\mathrm{Fl}\)
Newly formed atoms recoil into a physical/chemical separator and implant into position-sensitive detectors. Identification uses time-correlated decay chains (mostly \(\alpha\)-decay and sometimes spontaneous fission) with characteristic energies:
\(^{A}_{114}\mathrm{Fl} \;\xrightarrow{\alpha}\; ^{A-4}_{112}\mathrm{Cn} + \alpha \;\to\; \cdots\)
Observed isotopes include masses near \(A\approx 288\text{–}289\) (and neighbors). Half-lives range from milliseconds to seconds, sometimes reaching tens of seconds, enabling decay-chain assignment and limited single-atom surface-chemistry tests.
Gas-phase adsorption studies (on gold surfaces) and theory suggest Fl may be highly volatile and weakly adsorbing, potentially showing noble-metal-like or even noble-gas-like tendencies compared with Pb. This unusual inertness is attributed to strong relativistic effects in the 7s/7p shells.
Predicted condensed-phase states are mainly Fl(II) and possibly Fl(IV) under strongly oxidizing conditions. Hypothetical compounds include FlCl2, FlF2, and perhaps FlCl4/FlF4; however, direct aqueous chemistry has not been established due to extreme scarcity and short half-lives.
Experiments produce only a few atoms that decay quickly, so macroscopic samples cannot be prepared. Properties such as density, melting point, crystal structure, and color are therefore predictions from relativistic quantum calculations and atom-at-a-time surface chemistry.
Production (stylized fusion–evaporation):
\(^{244}\mathrm{Pu}(^{48}\mathrm{Ca},\,3n)\,^{289}\mathrm{Fl}\)
Generic decay step:
\(^{289}\mathrm{Fl} \;\xrightarrow{\alpha}\; ^{285}\mathrm{Cn} + \alpha\)