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Flerovium (Fl, element 114) is the heaviest element chemically studied so far. To date, its interaction with gold was investigated in two gas-solid chromatography experiments, which reported two different types of interaction, however, each based on the level of a few registered atoms only. Whereas noble-gas-like properties were suggested from the first experiment, the second one pointed at a volatile-metal-like character. Here, we present further experimental data on adsorption studies of Fl on silicon oxide and gold surfaces, accounting for the inhomogeneous nature of the surface, as it was used in the experiment and analyzed as part of the reported studies. We confirm that Fl is highly volatile and the least reactive member of group 14. Our experimental observations suggest that Fl exhibits lower reactivity towards Au than the volatile metal Hg, but higher reactivity than the noble gas Rn.

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The electron-capture decay followed by a prompt fission process was searched for in the hitherto unknown most neutron-deficient Md isotope with mass number 244. Alpha decay with α-particle energies of 8.73-8.86 MeV and with a half-life of 0.30 þ0.19 −0.09 s was assigned to 244 Md. No fission event with a similar half-life potentially originating from spontaneous fissioning of the short-lived electron-capture decay daughter 244 Fm was observed, which results in an upper limit of 0.14 for the electron-capture branching of 244 Md. Two groups of fission events with half-lives of 0.9 þ0.6 −0.3 ms and 5 þ3 −2 ms were observed. The 0.9 þ0.6 −0.3 ms activity was assigned to originate from the decay of 245 Md. The origin of eight fission events resulting in a half-life of 5 þ3 −2 ms could not be unambiguously identified within the present data while the possible explanation has to invoke previously unseen physics cases.

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