Tetra-sodium (dihydrogenhepta-oxido-digermanato)bis-(dihydrogentetra-oxido-germanato)dicopper(II) monohydrate

In the hydro/solvothermally synthesized title compound, Na(4)[Cu(2)(H(2)Ge(2)O(7))(H(2)GeO(4))(2)]·H(2)O, the framework building units include CuO(4), GeO(2)(OH)(2) and GeO(3)(OH) tetra-hedra, the latter being condensed into H(2)Ge(2)O(7) (4-) dimers. All the tetra-hedra are connected by corner-sharing into four-membered-ring (4MR) secondary building units containing two CuO(4), one GeO(2)(OH)(2) and one GeO(3)(OH) entity. The 4MRs form chains by corner-sharing the Cu unit and adjacent chains are linked by H(2)Ge(2)O(7) (4-) dimers, generating layers containing ten-membered rings. Three sodium cations (one with site symmetry and one with site symmetry 2) and a water mol-ecule (O-atom site symmetry 2) complete the structure. A network of O-H⋯O hydrogen bonds helps to consolidate the packing.