Received 6 November 2008
The structure of the binuclear title complex, [U2(C5H3N2O2)4O4(H2O)2]·2H2O, is composed of centrosymmetric dimers in which each UO22+ ion is coordinated by two ligand molecules. One donates its N,O-bonding group and the other donates both carboxylate O atoms. Each of the latter bridges adjacent uranyl ions. The coordination environment of the metal center is a distorted pentagonal bipyramid. The dimers are interconnected by O-HO hydrogen bonds between coordinated and uncoordinated water molecules and carboxylate O atoms. An intramolecular O-HN interaction is also present.
For the crystal structure of pyridazine-3-carboxylic acid hydrochloride, see: Gryz et al. (2003). For centrosymmetric dimeric molecules with a different bridging mode for the title ligand to calcium(II), see: Starosta & Leciejewicz (2007). For bond distances and angles in uranyl complexes with carboxylate ligands, see: Leciejewicz et al. (1995).
Data collection: KM-4 Software (Kuma, 1996); cell refinement: KM-4 Software; data reduction: DATAPROC (Kuma, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: RK2117 ).
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