Oxidants containing rhodium. X-ray photoelectroc spectra of dicaesium hexachlororhodate(iv), claus' blue and model compounds

Abstract

The X-ray photoeletron spectra of dicaesium hexachlororhodate(IV), tricaesium hexachlororhodate(III), a hydrated rhodium(III) oxide, and the barium salt of Claus' blue—previously formulated as a rhodate(VI)—suggest that the latter has rhodium(III) ions in an oxygen environment. ESR and Raman spectra of this blue solid confirm that the superoxide moiety is present. Prior work on higher oxidation states of rhodium in various environments is critically re-assessed. The compounds Cs 2[MCl 6] (M = Rh, Pt and Ir) are isomorphous by X-ray powder diffraction.