Combined neutron powder and X-ray single-crystal diffraction refinement of the atomic structure and hydrogen bonding of goslarite (ZnSO_4 centre dot 7H_2O)

摘要

The atomic structure of synthetic, deuterated goslarite (ZnSO_4 centre dot 7D_2O), a = 11.8176(6) A, b = 12.0755(7) A, c = 6.8270(4)A, space group P2_12_12_1, Z = 4, has been refined in a combined neutron powder diffraction and X-ray single-crystal data refinement to wRp 1.92 percent, Rp 1.45 percent and R(F~2) 12.66 percent for the neutron powder data contribution and R(F~2) 8.72 percent for the X-ray single-crystal data contribution. Both data sets were necessary to achieve the best overall fit agreement in the Rietveld refinement and reasonable geometry within structural units. The results of this study confirm that the H-bonding scheme for goslarite is the same as that of the other epsomite group minerals. Small but significant variations of the Zn-O bond lengths can be attributed to details of the H bonds to the O atoms of the Zn octahedra. This investigation of the atomic structure and hydrogen bonding of goslarite is groundwork for future studies into phase relationships and the mechanisms of hydration and dehydration in the ZnSO_4-H_2O system.