Nature: single-atom chemistry finds relativistic bond weakening in seaborgium hexacarbonyl

7 October 2026

A Nature paper published online on 7 October 2026 reports gas chromatography of seaborgium (Sg, Z = 106) hexacarbonyl, Sg(CO)6, one atom at a time.
The first bond dissociation energy of Sg(CO)6 is 188(9) kJ/mol, about 4(2) kJ/mol lower than for W(CO)6, its lighter group 6 homologue.
This reverses the trend of increasing energy across group 6 hexacarbonyls from W to Sg.
The result agrees with relativistic theory, which attributes the weakening to relativistic destabilisation of the 6d atomic orbitals in Sg.
The corresponding author, Alexander Yakushev, is at GSI Helmholtzzentrum, Darmstadt; only three of 75 registered Sg decay chains were assigned to Sg(CO)6.