Abstract | The atomic structure of synthetic, deuterated melanterite (FeSO₄·7D₂O), a 14.0774(9), b 6.5039(4), c 11.0506(7) Å, β 105.604(1)°, space group P21/c, Z = 4, has been refined from the combined refinement of 2.3731(1) Å and 1.3308 Å neutron powder-diffraction data to a Rwp(tot) = 3.01% and Rp(tot) = 2.18%. Both the short- and long-wavelength data were required to obtain a satisfactory fit in the Rietveld refinement. The results of this study confirm the previously proposed H-bonding scheme for melanterite. Small but significant variations of the Fe–O bond lengths are attributed to details of the hydrogen bonds to the oxygen atoms of the Fe octahedra. We draw comparisons between the monoclinic and orthorhombic heptahydrate sulfate minerals associated with mine wastes and relate differences in the structure to strengths and weaknesses in their H-bond networks. |
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