Title of article :
Redetermination of K2Mg3(OH)2(SO4)3(H2O)2 from single-crystal X-ray data revealing the correct hydrogen-atom positions
Author/Authors :
Weil, Matthias Institute for Chemical Technologies and Analytics - Division of Structural Chemistry, TU Wien, Austria
Abstract :
In comparison with the previous structure determination of K2Mg3(OH)2(SO4)3(H2O)2, dipotassium trimagnesium dihydroxide tris(sulfate) dihydrate, from laboratory powder X-ray diffraction data [Kubel & Cabaret-Lampin (2013[Kubel, F. & Cabaret-Lampin, M. (2013). Z. Anorg. Allg. Chem. 639, 1782-1786.]). Z. Anorg. Allg. Chem. 639, 1782–1786], the present redetermination against CCD single-crystal data has allowed for the modelling of all non-H atoms with anisotropic displacement parameters. As well as higher accuracy and precision in terms of bond lengths and angles, the clear localization of the H-atom positions leads also to a reasonable hydrogen-bonding scheme for this hydroxy hydrate. The structure consists of (100) sheets composed of corner- and edge-sharing [MgO6] octahedra and sulfate tetrahedra. Adjacent sheets are linked by the potassium cations and a hydrogen bond of medium strength involving the water molecule. The title compound is isotypic with its CoII and MnII analogues: the three K2M3(OH)2(SO4)3(H2O)2 (M = Mg, Co, Mn) structures are quantitatively compared.
Keywords :
structure comparison , hydrogen bonding , crystal structure , redetermination , potassium magnesium sulfate
Journal title :
Acta Crystallographica Section E: Crystallographic Communications