Poly[hexa­aqua­bis(μ(3)-naphthalene-2,6-dicarboxyl­ato)(μ(2)-naphthalene-2,6-dicarboxyl­ato)diholmium(III)]

The crystal structure of the title compound, [Ho(2)(C(12)H(6)O(4))(3)(H(2)O)(6)](n), contains binuclear centrosymmetric {Ho(2)O(2)(CO(2))(4)(H(2)O)(6)} cores inter­connected via the naphthalene-2,6-dicarboxyl­ate (NDC(2−)) bridging ligands into a two-dimensional neutral plane net, ∞(2)[Ho(2)(NDC)(3)(H(2)O)(6)], exhibiting a typical (4,4)-topology. Inter­actions between adjacent layers are assured by a series of C—H⋯π contacts and a number of strong and highly directional O—H⋯O hydrogen bonds involving the coordinated water mol­ecules and neighbouring coordinated carboxyl­ate groups. One NDC(2−) bridging ligand has its centroid located at a crystallographic centre of inversion.