Poly[tetra-aqua-(μ(6)-9,10-dioxo-9,10-dihydro-anthracene-1,4,5,8-tetra-carboxyl-ato)dimanganese(II)].

The title complex, Mn(2)(C(18)H(4)O(10))(H(2)O)(4), was synthesized from manganese(II) chloride tetra-hydrate and 9,10-dioxo-9,10-dihydro-anthracene-1,4,5,8-tetra-carb-oxy-lic acid (H(4)AQTC) in water. The anthraquinone unit is located about a crystallographic center of inversion. Each asymmetric unit therefore contains one Mn(II) atom, two water ligands and one half AQTC(4-) anion. The Mn(II) atom is coordinated in a distorted octa-hedral geometry by four O atoms from three AQTC(4-) ligands and two water O atoms. Two of the carboxyl-ate groups coordinate one Mn(II) atom in a chelating mode, whereas the others each coordinate two Mn(II) atoms. Each AQTC(4-) tetra-anion therefore coordinates six different Mn(II) ions and, as a result, a three-dimensional coordination polymer is formed. O-H⋯O hydrogen bonds, some of them bifurcated, between water ligands and neighboring water or anthraquinone ligands are observed in the crystal structure.