Commensurate Monoclinic Form of Ca2Zn0.97Co0.03Ge2O7

Cobalt-doped dicalcium zinc germanate, synthesized by slow cooling from the melt, is monoclinic and has a layered structure, which is different from the modulated melilite-type structure of Ca2ZnGe2O7. The monoclinic form has two different Ca, one Zn and two Ge sites, and seven independent O-atom positions; all are in general position 4e of the space group P21/n. The topology of the structure is described and compared with that of Ca2ZnGe1.25Si0.75O7.