Poly[[dodeca­aqua­hexa­kis­(μ2-pyridine-2,5-dicarboxyl­ato)tricopper(II)diytterbium(III)] dihydrate]

The asymmetric unit of the title heterometallic coordination polymer, {[Cu(3)Yb(2)(C(7)H(3)NO(4))(6)(H(2)O)(12)]·2H(2)O}(n), contains one Yb(III) and two Cu(II) atoms. The Cu(II) atom that is located on an inversion center is N,O-chelated by two pyridine-2,5-dicarboxyl-ate (pdc) anions in a square-planar geometry; the Cu atom located on a general position is N,O-chelated by two pdc anions in the basal plane and is further coordinated by a water O atom at the apical position in a distorted square-pyramidal geometry. The Yb(III) atom is eight coordinated in a distorted square-anti-prismatic geometry formed by three carboxyl-ate O atoms from three pdc anions and five water mol-ecules. The pdc anions bridge adjacent Yb(III) and Cu(III) atoms, forming a three-dimensional polymeric structure. The crystal structure contains extensive O-H⋯O hydrogen bonds. π-π stacking is present in the crystal structure, the shortest centroid-centroid distance between parallel pyridine rings of adjacent mol-ecules being 3.646 (3) Å.