Introducing oganesson tetratennesside

If the two heaviest elements in the periodic table had a chance to react, they could form a stable pentatomic molecule, according to the first computational study of its type to examine the properties of a molecule composed of tennessine (element 117) and oganesson (element 118) (Theor. Chem. Acc. 2021, DOI: 10.1007/s00214-021-02777-2). The study explores the chemistry of a molecule that has yet to be created and may guide future experiments. It also offers a test case for examining the effects of relativity, such as spin-orbit coupling, which strongly affects heavy elements and causes complex shifts in their electronic energy levels. To probe the properties of OgTs₄, a team led by Gulzari L. Malli of Simon Fraser University compared the results of relativistic and nonrelativistic analyses, both of which are computationally intense. The relativistic computations indicate that OgTs₄ is a stable molecule, likely to adopt tetrahedral geometry, which for this molecule is roughly 1 eV more stable than the square planar version. Omitting the effects of relativity leads to several erroneous predictions, most notably that OgTs₄ isn’t stable enough to be bound. The study shows that for the heaviest elements, relativity must be addressed rigorously, says Paul J. Karol, a Carnegie Mellon University scientist, who was not involved in the work. “Chemical intuition doesn’t help because relativity scrambles everything,” he says.