title: Bis(4,4'-bipyridinium) dodeca-tungsto-silicate 4,4'-bipyridine hexa-hydrate.
abstract: The title compound, (C(10)H(10)N(2))(2)[SiW(12)O(40)]·C(10)H(8)N(2)·6H(2)O or (4,4'-bipyH(2))(2)[SiW(12)O(40)].(4,4'-bipy)·6H(2)O (4,4'-bipy is 4,4'-bipyridine), was prepared under hydro-thermal conditions. The asymmetric unit contains a discrete Keggin-type [SiW(12)O(40)](4-) anion (located on a twofold axis), one 4,4'-bipy (located on a twofold axis), two (4,4'-bipyH(2))(2+) cations and six uncoordinated water mol-ecules. The polyoxoanion is constructed from a central SiO(4) tetra-hedron which shares its O atoms with four trinuclear W(3)O(13) groups, each of which is made up of three edge-sharing WO(6) octa-hedra. The water mol-ecules and [SiW(12)O(40)](4-) anions are linked through hydrogen bonds.
authors.forename: Feng-Xia
authors.initials: FX
authors.lastname: Ma
authors.forename: Quan
authors.initials: Q
authors.lastname: Zhao