Ca3ZnGeO2[Ge4O12]: a Ca–Zn germanate related to the mineral taikanite

The title compound, Ca₃ZnGeO₂Ge₄O₁₂] (tricalcium zinc germanium dioxide dodecaoxidotetragermanate), adopts a taikanite‐type structure. The tetrahedral Ge₄O₁₂] chain geometry is very similar to that of the silicate chain of taikanite, i.e. BaSr₂Mn³⁺₂O₂Si₄O₁₂], while the major difference is found parallel to the c axis. In taikanite, Mn³⁺ octahedra form an infinite zigzag chain, whereas the title compound has a chain of distorted ZnO₆ octahedra, which alternates with distorted GeO₄ tetrahedra connected to each other via two common edges. Eightfold‐coordinated Ca²⁺ polyhedra and ZnO₆ octahedra form a slab parallel to (001) which alternates with another slab containing the tetrahedrally coordinated Ge sites along the c axis.