A Dirac molecular orbital study for the tetragonal compression in the RuY6I122− cluster

Symmetry-adapted angular momentum basis functions have been generated for the Oh∗* and D4h∗* molecular double point groups. These basis functions are used to obtain the relativistic cluster orbitals for the octahedral (Oh) and the compressed octahedral geometries (D4h) of the RuY6I122− cluster. The Jahn-Teller effect removes the octahedral Γ8− orbital degeneracy, thus giving rise to a stable tetragonal cluster with a singlet Γ7− ground state. The interstitial Ru atom acquires more electrons in the tetragonally compressed cluster structure than in its octahedral arrangement.