title: catena-Poly[[(3,5-dicarb-oxy-pyrazine-2,6-dicarboxyl-ato-κO,N,O)lithium(I)]-μ-aqua-[triaqua-lithium(I)]-μ-aqua].
abstract: The title coordination polymer, [Li(2)(C(8)H(2)N(2)O(8))(H(2)O)(5)](n) contains two symmetry-independent Li(+) ions; one is coordin-ated by five water O atoms, the other by an O,N,O'-tridentate doubly deprotonated pyrazine-2,3,5,6-tetra-carboxyl-ate ligand and two water O atoms. Water mol-ecules bridge adjacent Li(+) ions into ribbons propagating in [100]; an alternative analysis of the structure considers it to contain alternating [Li(C(8)H(2)N(2)O(8))(H(2)O)(2)](-) anions and [Li(H(2)O)(3)](+) cations. In the polymeric model, both lithium ions show distorted trigonal-bipyramidal coordination geometries. Within the ligand, the carboxyl H atoms participate in short, almost symmetric O⋯H⋯O hydrogen bonds in which the non-coordinated carboxyl-ate O atoms are donors and acceptors. In the crystal, the ribbons inter-act via a network of O-H⋯O hydrogen bonds in which the coordinated water mol-ecules act as donors and ligand carboxyl-ate O atoms as acceptors.
authors: Institute of Nuclear Chemistry and Technology, ul. Dorodna 16, 03-195 Warszawa, Poland.
authors: Wojciech
authors: W
authors: Starosta
authors: Janusz
authors: J
authors: Leciejewicz
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