The NaDyBr₄ complex; its molecular structure and thermodynamic properties

The molecular geometry, vibrational frequencies, relative stabilities, and some thermodynamic properties of different isomers of the NaDyBr₄ complex were determined by computation. We investigated, to our knowledge for the first time for such a complex, the possible effect of the partially filled 4f orbitals on the molecular properties of an MLnX₄ complex by using a "small core" effective core potential of the Stuttgart group. The tridentate complex, with three Na-Br bridges, was found to be the ground-state structure with the bidentate one only about 4-6 kJ/mol higher in energy. The relative abundance of these isomers changes with temperature and at the high-temperature conditions of a metal halide lamp the bidentate isomer is the more abundant isomer.