Poly[tris­(2,5-dimethyl­benzene-1,4-­dicarboxyl­ato)bis­(pyridine)trizinc(II)]

The asymmetric unit of the title polymeric compound, [Zn(3)(C(10)H(8)O(4))(3)(C(5)H(5)N)(2)](n) or [Zn(3)(dmbdc)(3)(py)(2)](n) (dmbdc = 2,5-dimethyl­benzene­dicarboxyl­ate; py = pyridine) contains two Zn(II) ions, one of which is located on an inversion centre, one and a half 2,5-dimethyl­benzene­dicarboxyl­ate ligands and one pyridine ligand. Each ZnO(6) octa­hedron is sandwiched between two ZnO(4)N square-pyramids, forming a trinuclear zinc secondary building unit (SBU); each SBU is further linked by six 2,5-dimethyl­benzene­dicarboxyl­ate ligands with six adjacent trinuclear zinc SBU’s, forming a two-dimensional layer structure with a (3,6) net. One of the three zinc ions is octa­hedrally coordinated and the other two are square-pyramidally coordinated. The coordination modes for 2,5-dimethyl­benzene­dicarboxyl­ates are bis­(bidentate) or bidentate-tridentate.