The vibrational spectra of diiodohalogenomercurate(II) anions in the solid state

Diiodobromo and diiodochloromercurate(II) anions as salts of tetrapropylammonium (pr₄N) have been prepared, characterized and their far i.r. and Raman spectra measured at room and liquid nitrogen temperature. The bands observed in the stretching frequency region indicate strong halide-bridged interactions in the solid state and hence the compounds are better formulated as (pr₄N)₂ Hg₂I₄X₂ with X (X = Cl or Br) as the bridging ligands. Group vibrations are tentatively assigned to type I distorted structure.