Hydrogen bonding in goldichite, KFe(SO4)2•4H2O: structure refinement

The crystal structure of goldichite KFe(SO4)(2)ai...4H(2)O was determined on a single crystal from the Baiyinchang copper deposit, Gansu, China. [P12(1)/c1, a = 10.395(2), b = 10.475(2), c = 9.0875(18) , beta = 101.65(3)A degrees, V = 969.1(3) (3), Z = 4]. All non-H atoms were refined with anisotropic displacement parameters and positions of H-atoms were determined by difference Fourier methods and refined from X-ray diffraction data. The crystal structure of goldichite consists of corrugated sheets parallel to the (100) plane by sharing corners between FeO6 octahedra and SO4 tetrahedra. The interstitial potassium atom exhibits a [KO7(H2O)(2)] nine-fold coordination, which shares edges to form a column parallel to the c-axis and to build a slab with the corrugated sheet. These slabs are linked in the [100] direction through a network of hydrogen bonds. Three types of hydrogen bonds involve links of slabs: O-w(3)-H(3B)center dot center dot center dot O(1), O-w(6)-H(6B)center dot center dot center dot O(11) and O-w(9)-H(9B)center dot center dot center dot O(11). The FTIR spectrum of goldichite shows a strong absorption between similar to 3384 cm(-1) and similar to 3592 cm(-1), which is in accordance with the O-H center dot center dot center dot O distances derived from structure data.