Zur Kenntnis von Calciumtetrahydrogen-hexaoxo-diperiodattetrahydrat CaH4I2O10 · 4 H2O: Kristallstruktur, Schwingungsspektren und thermische Analyse / On Calciumtetrahydrogen-hexaoxo-diperiodatetetrahydrate CaH4I2O10 · 4 H2O: Crystal Structure, Vibrational Spectroscopy and Thermal Analysis

Abstract

By crystallisation from a strongly acidic aqueous solution calciumtetrahydrogen-hexaoxo-diperiodatetetrahydrate CaH4I2O10 ∙ 4 H2O has been obtained. In the structure of this compound (S.G. C2/c, Nr. 15), Z = 4, a = 1986,6(4), b = 564,2(1), c = 1149,4(20) pm, β = 120,62(3)°) centrosymmetric H4I2O10 2− anions in the form of edge-sharing octahedra form layers via hydrogen bonds originating from the acidic, trans-configurated OH groups of the anions. IR and Raman spectra are analysed with respect to the hydrogen bond system and the internal vibrations of the periodate anion. The dehydration of the compound takes place via Ca(IO4)2 ∙ 5 H2O and Ca(IO4)2 ∙2H2O leading at 143°C to the anhydrous metaperiodate Ca(IO4)2 which decomposes above 248°C to Ca(IO3)2.