Poly[[tetra­aqua­tetra­kis­[μ(3)-5-(pyridine-4-carboxamido)­isophthalato]cobalt(II)dierbium(III)] tetra­hydrate]

In the centrosymmetric polymeric title compound, {[CoEr(2)(C(14)H(8)N(2)O(5))(4)(H(2)O)(4)]·4H(2)O}(n), the Er(III) cation has a coordination number of eight and is surrounded by seven carboxyl­ate O atoms from four 5-(pyridine-4-carboxamido)­isophthalate (L) ligands and one water mol­ecule, forming a distorted square-anti­prismatic arrangement. The Co(II) cation is located on an inversion center and is coordinated by two pyridine N atoms, two carboxyl­ate O atoms and two water mol­ecules in a distorted octa­hedral geometry. The asymmetric unit contains two anionic L ligands. One bridges two Er(III) cations and one Co(II) cation through two carboxyl­ate groups and one pyridine N atom, while the other bridges two Er(III) cations and one Co(II) cation through two carboxyl­ate groups. Extensive O—H⋯O, O—H⋯N and N—H⋯O hydrogen-bonding inter­actions are present in the crystal, involving all uncoordinated water mol­ecules and the uncoordinated pyridine N atom of one of the ligands bonded to an adjacent coordinated water mol­ecule. The title compound is isotypic with the gadolinium analogue.