On the Existence and Stability of Cations of d- and f-Transition Elements in Acidic Non-Aqueous Media

Recently observed spectra of solvated d- and f-transition element cations in superacidic media, together with spectra of aqua cations in acidic aqueous solution, are used to propose that cationic speciation is much more general in acidic solvents and melts than is usually accepted. It will be shown that cations in unusually low oxidation states are stabilized in highly acidic media, and that these cations disproportionate as the acidity of the medium is decreased and that in general these latter phenomena are independent of the chemical nature or the temperature domain of the medium.