Lawrence Berkeley National Laboratory

It is expected that the chemical properties of the heaviest of the superheavy elements (SHEs, Z = 113 – 118) do not align with what is suggested by their current positions on the periodic table. Specifically, the onset of significant relativistic effects, including increased spin–orbit splitting of the p-orbitals may lead to enhanced stability of low-oxidation states. Notably, it is predicted that flerovium ( Z = 114) may exhibit pseudo-noble gas behavior from a 7p1/22 electron configuration that acts as an ‘inert pair’. Even though it is expected that the p1/2– p3/2 splitting becomes pronounced toward the end of the p-block’s sixth row, there is currently limited experimental evidence to confirm its extent or impact. Here, the production of gas-phase lead ( Z = 82) and polonium ( Z = 84) fluoride cations (PbF n+ and PoF n+) were compared to elucidate differences in accessible oxidation states. The PoF n+ and PbF n+ species were produced and identified with the FIONA spectrometer at the Lawrence Berkeley National Laboratory 88-Inch Cylctron Facility. Polonium showed notably different fluorination chemistry than lead, producing PoF + and PoF 3+ as primary products compared to lead’s PbF + and PbF 2+. The distribution of PoF n+ products observed offer insights as to the role of spin–orbit splitting for polonium. Similar studies of superheavy elements would elucidate the accessibility of their low-oxidation states as well as to inform chemical predictions for eighth-row elements not yet discovered.