Acta Cryst. (2007). E63, m2069-m2070  [ doi:10.1107/S1600536807032059 ]

Poly[[tetraaquabis(5-carboxypyridine-2-carboxylato-²N,O)bis(₄-pyridine-2,5-dicarboxylato-⁵N,O:O:O':O'')dilanthanum(III)] dihydrate]

F. Zhang, B. Yu, X.-Q. Wang, G.-Q. Shen and D.-Z. Shen

Abstract: The title compound, {[La₂(C₇H₄NO₄)₂(C₇H₃NO₄)₂(H₂O)₄]·2H₂O}_n, was prepared by a hydrothermal reaction at 433 K. The asymmetric unit contains two La^III ions. Each La^III ion is nine-coordinated in a slightly distorted tricapped trigonal-prismatic coordination geometry, formed by two N atoms from 5-carboxypyridine-2-carboxylate (Hpydc) and pyridine-2,5-dicarboxylate (pydc) ligands, five O atoms from carboxylate groups of one Hpydc and four pydc ligands, and two water molecules. Adjacent La^III ions are linked together through single bridging carboxylate O atoms and carboxylate groups in a syn-anti mode, forming a two-dimensional layered polymeric structure. Extensive O-HO hydrogen bonding connects adjacent layers into an infinite three-dimensional supramolecular network structure. The crystal studied was an inversion twin.

Online 5 July 2007

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