Schaurteite, Ca 3 Ge(SO 4 ) 2 (OH) 6 ·3H 2 O

This report presents the first crystal structure determination of the mineral schaurteite, ideally Ca 3 Ge(SO 4 ) 2 (OH) 6 ·3H 2 O, tricalcium germanium bis(sulfate) hexahydroxide trihydrate. This single-crystal X-ray diffraction study investigated a natural sample from the type locality at Tsumeb, Namibia. Schaurteite is a member of the fleischerite group of minerals, which also includes fleischerite, despujolsite, and mallestigite. The structure of schaurteite consists of slabs of Ca(O,OH,H 2 O) 8 polyhedra (site symmetry mm 2) interleaved with a mixed layer of Ge(OH) 6 octahedra (-3 m .) and SO 4 tetrahedra (3 m .). There are two H atoms in the asymmetric unit, both located by full-matrix refinement, and both forming O—H...O hydrogen bonds.