Synthesis and crystal structure of Cs2(CN3H6)3[(C2H5)2NH2][W7O22(O2)2]•3H2O

A novel diperoxoheptatungstate was crystallised as a Cs+-CN3H6+-(C2H5)(2)NH2+ salt and characterised by a single-crystal X-ray diffraction method. The anion has a Lindqvist heptametallate structure. The metal atoms are located in a bent 2-3-2 arrangement with the central W-3 section (W3, W4 and W5) as the hinge. The peroxo groups coordinate the tungsten atoms at both ends of the W3 section (W3 and W5). In the crystal polyanions, caesium and guanidinium cations, and water of crystallisation form tunnel-like cavities, and the diethylammonium cations are accommodated in the cavities, suggesting a clathrate-like feature for the compound. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004).