Zur Kenntnis der Sulfite und Sulfithydrate des Zinks, Mangans, Magnesiums und Cobalts — Röntgenographische, spektroskopische und thermoanalytische Untersuchungen / Sulfites and Sulfite Hydrates of Zinc, Manganese, Magnesium and Cobalt-X-ray, Spectroscopic and Thermoanalytical Data

Abstract

IR, Raman, and X-ray data of ZnSO3 · 2½ H2O, ZnSO3 · 2 H2O, ZnSO3 ·½ H2O, ZnSO3, MnSO3 · 3 H2O, MnSO3 · H2O, MnSO3, MgSO3 · 6 H2O, MgSO3 · 3 H2O, CoSO3 · 3 H2O, CoSO3 · 2½ H2O, and CoSO3·2 H2O are presented. Except of MgSO3·6 H2O and ZnSO3 · 2½ H2O the crystal structures of these compounds are yet unknown. The following crystal data could be determined by single crystal measurements: ZnSO3 · 2 H2O (monoclinic, P21/n) : a = 642.1, b = 852.4, c = 757.4 pm, β = 98.93°, Z = 4, MnSO3 · 3 Η2Ο (monoclinic, Ρ21/n) : a = 665.0, b = 890.6, c = 879.3 pm, ß = 96.11°, Z = 4, MnSO3 · Η2Ο (orthorhombic) : a = 2565.1, b = 483.9, c = 576.0 pm, Z = 8, CoSO3 · 3 Η2Ο (orthorhombic, Pna21, isotype with MgSO3 · 3 H2O): a = 952.7, b = 942.0, c = 552.1 pm, Z = 4, CoSO3• 2½ H2O (tetragonal) : a = b = 946.4, c = 1021.1 pm, Z = 8, CoSO3 · 2 H2O (isotype with ZnSO3 · 2 H2O) : a = 639.7, b = 855.3, c = 753.7 pm, β = 98.85°, Z = 4. The IR spectra show that with exception of MnSO3· H2O strong hydrogen bonds are present in the sulfite hydrates. The decomposition of the sulfites has been examined by thermal analysis. Dehydration of the sulfite hydrates starts at 90 (ZnSO3 · 2½ H2O), 120 (ZnSO3 · 2 H2O), 175 (ZnSO3 · 1/2 H2O), 85 (MnSO3 · 3 H2O), 205 (MnSO3 · H2O), 70 (MgSO3 · 6 H2O), 130 (MgSO3 · 3 H2O), 120 (CoSO3 · 3 H2O), 140 (CoSO3 · 2½ H2O), and 150 °C (CoSO3 · 2 H2O). Decomposition of the anhydrous sulfites occurs at 300-350 (ZnSO3), 390-460 (MnSO3), and 400-530 °C (MgSO3).