catena-Poly[[[diaqua-terbium(III)]-tri-μ(2)-isonicotinato-κO:O'] tris(perchlorate) monohydrate].

In the title complex, {Tb(C(6)H(5)NO(2))(3)(H(2)O)(2)(3)·H(2)O}(n), the Tb(III) ion is coordinated by six O atoms from six isonicotinate (inic) ligands and two water mol-ecules, displaying a bicapped trigonal-prismatic geometry. The inic ligands, which are protonated at the pyridine N atom, link the metal centres, forming a polymeric chain running parallel to the a axis. The chains are further assembled via intra- and inter-molecular O-H⋯O and N-H⋯O hydrogen-bonding inter-actions into a three-dimensional supra-molecular network involving the inic ligands, the water mol-ecules and the perchlorate anions. One of the perchlorate ions is disordered over two sites with occupancies of 0.561 (17) and 0.439 (17).