Poly[[bis{μ3-2-[(3,5-dimethyl-1H-pyrazol-1-yl)(phenyl)methyl]propanedioato}tetrasodium(I)] 7.5-hydrate]

The asymmetric unit of the title polymer, {[Na-4(C15H14N2O4)(2)]center dot 7.5H(2)O} (n) , contains two 2-[(3,5-dimethyl-1H-pyrazol-1-yl)(phenyl)methyl]propanedioate (ppmp) anions, eight water molecules (one located on a twofold rotation axis) and five sodium cations (one located on an inversion center and the other one located on a twofold rotation axis). The carboxylate groups of the ppmp anions and the water molecules bridge the Na cations, forming a two-dimensional polymeric structure. In the structure there are two types of coordination environment around the metal cations: one Na cation is coordinated by five O atoms in a distorted square-pyramidal geometry while the other four Na cations are coordinated by six O atoms in a distorted octahedral geometry. Extensive O-H...O and O-H...N hydrogen bonding is present in the crystal structure. The H atoms of one methyl group of the ppmp anion are disordered equally over two positions.