A commensurately modulated structure of parabutlerite, (FeSO4)-S-III(OH)center dot 2H(2)O

作者：Plasil Jakub^*; Petricek Vaclav; Majzlan Juraj

来源：Acta Crystallographica Section B-Structural Science Crystal Engineering and Materials, 2017, 73(5): 856-862.

DOI：10.1107/S2052520617007156

• parabutlerite
• ferric sulfate hydrate
• modulated structure
• commensurate

Parabutlerite, orthorhombic (FeSO4)-S-III(OH)center dot 2H(2)O, has been reinvestigated using single-crystal X-ray diffraction. The structure of parabutlerite is commensurately modulated, with a = 20.0789 (8), b = 7.4024 (7), c = 7.2294 (15) angstrom and q = 0.4b*. The superstructure has been determined, using a superspace approach, as having the superspace group Pnma(0 beta 0)s0s and t(0) = 1/20, and refined to R = 0.0295 for 2392 main reflections with I > 3 sigma(I). The structure consists of infinite chains of Fe octahedra that are linked via vertices (OH groups); these chains are encased from both sides by SO4 tetrahedra. The displacive modulation of atoms in parabutlerite is connected with a tilt of the chains around the b axis towards the adjacent chains due to the accommodation of an energetically more favorable hydrogen-bond geometry.

• 出版日期2017-10