Hydrothermal synthesis and structural characterizations of two new germanates with a novel topological framework and unusual Ge4(OH)4 cubane

Two new germanates, Ge7O12(OH)4 (C4N3H13)(0.5)(H2O)5 (1) and Ge7O12(OH)4(H2O)6 (2) have been synthesized under hydrothermal conditions and characterized by IR spectroscopy, powder XRD, TG, and single-crystal X-ray diffraction. Compound 1 crystallizes in cubic space group P3m (No. 215) with a = b = c = 7.7119(5) A, v = 458.65(5) A(3), z = 1. Compound 2: cubic, P3m, a = b = c = 7.7653(17) A, v = 457.48(17) A(3), z = 1. Both germanates keep the same topological novel inorganic framework, which is assembled from Ge4(OH)4 cubane and chiral intertwined Ge-O double helices.