Abstract
In the title compound, [Ca(C(5)H(2)N(2)O(4))(H(2)O)](n), the Ca(2+) cations are eigthtfold coordinated by six O atoms and one N atom of four symmetry-related anions and one water mol-ecule within an irregular polyhedron. These CaO(7)N polyhedra are connected via the anions into a three-dimensional network. The anions are additionally linked by N-H⋯O and O-H⋯O hydrogen bonding.