Vibrational spectrum and structure of the ICl+2 cation

The Raman spectra of the antimony and aluminium complexes SbICl₈ and AlICl₆, known to contain the ICI⁺₂ cation, are presented. Partial infrared spectra (to 200 cm^?1) are also measured. Bands belonging to the bent ICl⁺₂ cation (C_2v) and also to the anionic components of the complexes, SbCl^?₆ and AlCl^?₄, have been identified and assigned. Force constants, calculated for ICl⁺₂, are shown to be in good agreement with corresponding constants of other isoelectronic ions.