X-ray diffraction study of Na₂S₂O₆.2H₂O and Na₂S₂O₆.2D₂O

Abstract

The crystal structures of Na2S206.2H20 and its deuterated homologue Na2S206.2D20 have been reinvestigated by single-crystal X-ray diffractometry. Conventional refinements of both data sets with the assumption of neutral S and O atoms yielded agreement factors of Runobs.omittecl = 0.0198 and 0.0229 respectively. The geometric results of both compounds investigated on different diffractometers show a high degree of agreement, indicating the absence of bias due to systematic experimental errors.

Elastic properties of the dithionates Na2S2O6 · 2 H2O, K2S2O6, Rb2S2O6, CaS2O6 · 4H2O and SrS2O6 · 4 H2O

“…The morphological point symmetry group of Na,S,O, ' 2 H,O is mmm in accordance with space group Pnma reported by various authors (see e.g. KIRFEL et al 1980). In the case of the four other dithionates under consideration all individuals exhibit a distinct hypermorphy : crystals of K,S,O, and Rb,S206 are frequently twinned and show 6/mm symmetry without any striations.…”

“…The sodium salt has been used by KIRFEL et al (1980) for a detailed structural investigation of bonding in the SzOganion. Hitherto the elastic properties of dithionates have not yet been reported in the literature with the exception of Cs,S,O, which crystallizes in point symmetry group 6 m and exhibits large piezoelectric and electrooptic effects (HAUSSUHL 1978).…”

Bonding in [S2O6]2−: refinement and pictorial representation from an X-ray diffraction study of Na2S2O6.2H2O and Na2S2O6.2D2O

“…The SAM is modified only marginally, indicating that the classical chemical models employing greater deviations from atomic neutrality, such as S 4+, O 2-, etc., must be discarded as inadequate (cf. Kirfel, Will & Weiss, 1980;Berthold & Weiss, 1967). Consequently, it seems advisable for conventional refinement purposes to treat similar anion complexes such as [SO4] 2-or [SiO4] 2-as neutral-atom arrangements rather than allocate scattering factors derived from chemical considerations (see also Will, Frazer, Shirane & Cox, 1965).…”

“…In a previous paper (Kirfel, Will & Weiss, 1980; hereafter called part I) the crystal structures of Na2S 2-O6.2H20 and its deuterated homologue have been reinvestigated and refined by conventional least-squares methods from X-ray diffraction data. As in part I, the compounds are referred to as NAH and NAD respectively.…”