Relativistic effects for the superheavy reaction Og + 2Ts 2 → OgTs 4 (T d or D 4h ): dramatic relativistic effects for atomization energy of superheavy Oganesson tetratennesside OgTs 4 and prediction of the existence of tetrahedral OgTs 4

Our all-electron fully relativistic Dirac–Fock (DF) and nonrelativistic (NR) Hartree–Fock SCF molecular calculations for the superheavy tetrahedral (Td) oganesson tetratennesside OgTs 4 predict atomization energies (A e ) of 7.45 and −11.21 eV, respectively. Our DF and NR calculations, however for the square planar (D 4h ) OgTs 4 predict atomization energies (A e ) of 6.34 and −8.56 eV, respectively. There are dramatic relativistic effects for the atomization energies of T d and D 4h OgTs 4 of ~ 18.65 eV and ~ 14.90 eV, respectively. Whereas our DF calculations predict the T d OgTs 4 to be more stable than the D 4h OgTs 4 by ~ 1.10 eV, our NR calculations predict the D 4h OgTs 4 to be more stable than the T d OgTs 4 by ~ 2.65 eV. Our NR calculations predict both the T d and D 4h OgTs4 to be unbound by 11.21 and 8.56 eV, respectively. However, our relativistic DF calculations predict both the T d and D 4h OgTs 4 to be bound by 7.45 and 6.34 eV, respectively, and so the relativistic treatment is mandatory for bonding and binding in the pentatomic superheavy system with 586 electrons involving the two heaviest SHE Ts and Og.