2.2.3. [Cd(en)3]{[Cd(η2-en)2]3[Cd(η2-en)(η1-en)(η2-en)Cd][Ge6V15O48(H2O)]}·5.5H2O (**3**)

GeO2 (0.104 g, 1.00 mmol), NH4VO3 (0.2323 g, 2.00 mmol) and CdCl2 (0.1831 g, 1.00 mmol) were added to a 25% aqueous solution of en (6.00 mL). The resulting suspension was further stirred for 12 h, then 2, 2 -bpy (0.156 g, 1.0 mmol) were added, the final mixture (pH 9.7–10) was moved to a 35 mL Teflon-lined autoclave, sealed and kept at 170 ◦C for 5 days and then it was cooled to ambient temperature. Black square crystals were collected by filtration and washed with water (Yield: 0.413 g, 71.20% based on GeO2). Anal. Calcd for C24H109Cd6Ge6N24O54.5V15: C, 8.28; H, 3.16; N, 9.66%. Found: C, 8.19; H, 3.00; N, 9.63%.
