Ground state of octahedral platinum hexafluoride

All previously published nonrelativistic and scalar relativistic electronic structure calculations of platinum hexafluoride predict a paramagnetic distorted octahedral molecule with a triplet ground state. The four-component spin-free method also predicts a distorted octahedral molecule with longest axial Pt-F bond due to the Jahn-Teller effect. However, four-component Dirac molecular Hartree-Fock and density-functional theory DFT and the two-component zeroth-order regular approach ZORA including spin-orbit interaction calculations predict a diamagnetic octahedral molecule with a closed-shell ground state, which is in accordance with the observation of the ¹⁹F and ¹⁹⁵Pt high-resolution nuclear magnetic resonance spectra and its undisturbed ir and Raman spectra of PtF₆. The excitation energies involving the d-d transitions are well calculated by performing time-dependent DFT calculations using the two-component ZORA method. Thus, its octahedral molecular structure with a closed-shell ground state is stabilized by the effect of a spin-orbit interaction.