Poly[[diaqua(mu3-3-nitrophthalato)calcium(II)] monohydrate].

The title 3-nitrophthalate-calcium coordination polymer, {[Ca(C8H3NO6)(H2O)2].H2O}n, crystallizes as a one-dimensional framework. The Ca(II) centre has a distorted pentagonal-bipyramidal geometry, being seven-coordinated by five O atoms from three different 3-nitrophthalate groups and by two water molecules, resulting in a one-dimensional zigzag chain along the a-axis direction by the interconnection of the four O atoms from the two carboxylate groups. There is a D3 water cluster composed of the coordinated and the solvent water molecules within such chains. Adjacent chains are aggregated into two-dimensional layers via hydrogen bonds in the c-axis direction. The whole three-dimensional structure is further stabilized by weak O-H...O hydrogen bonds between the O atoms of the nitro group and the water molecules.