Polyoxotungstates containing uranyl group: Germanotungstates with Keggin sandwich structure

Two new polygermanotungstates containing uranyl group A-alpha-Na-14[Na-2(UO2)(2)(GeW9O34)(2)]center dot 48H(2)O (1) and A-beta-Na-14[Na-2(UO2)(2)(GeW9O34)(2)]center dot 42H(2)O (2) have been synthesized and characterized by elemental analysis, IR and single-crystal X-ray diffraction. Both the two polyanions consist of two [GeW9O34](10-) units which sandwich two UO22+ cations and two Na+ cations. The two uranium atoms are similar to each other, that is, each uranium is pentagonal-bipyramidal coordination achieved by three equatorial U-O bonds to one GeW9O34 and two U-O bonds to the other. (C) 2006 Elsevier B.V. All rights reserved.