catena-Poly[[diaqua­(isonicotinato-κ2 O, O′)erbium(III)]-di-μ-isonicotinato-κ4 O: O′].

In the title compound, [Er(IN)3(H2O)2] n, where IN is the isonicotinate anion, C6H4NO2−, the asymmetric unit contains one half-mol­ecule. The ErIII atom lies on a crystallographic twofold axis and is coordinated by four and two carboxyl­ate O atoms from bridging and chelating isonicotinate groups, respectively, and by two O atoms from water mol­ecules, yielding an eight-coordinate square-anti­prismatic geometry. In the crystal structure, the polymer features an infinite doubly carboxyl­ate-bridged chain-like structure with one chelating carboxyl­ate group on each metal centre. Adjacent chains are, in turn, connected to each other through inter­molecular O—H⋯O and O—H⋯N hydrogen bonds, forming a three-dimensional network. [ABSTRACT FROM AUTHOR]