Heavy-alkali selenate and sulfate complexes with periodic acid and periodates

The complexing features of heavy-alkali selenates and sulfates with periodic acid and periodates are studied. Adducts CsHSeO4 · 2CsH4IO6, CsHSeO4 · H5IO6 and MHSO4 · H5IO6 with M = Cs, Rb, or K are isolated for the first time, and conditions are found for preparing adduct CsHSO4 · 2CsH4IO6 in an individual state. The adducts are characterized by IR spectroscopy, X-ray powder diffraction, thermal analysis, and chemical analysis. They do not contain hydrosulfate or hydroseleante anions as shown by their IR spectra. All protons are bound to iodine-oxygen octahedra to form hydrogen biperiodate anion [H(H4IO6)2]− or hexahydroxoiodonium cation [H6IO6]+.