Ammonium tris-(3-amino-pyrazine-2-carboxyl-ato-κN,O)nickelate(II) trihydrate.

The Ni(II) atom in the title hydrated salt, (NH(4))[Ni(C(5)H(4)N(3)O(2))(3)]·3H(2)O, is N,O-chelated by the three 3-aminopyrazine-2-carboxyl-ate ligands, resulting in a distorted octa-hedral mer-NiN(3)O(3) geometry for the metal. In the crystal, the complex anion, ammonium cation and uncoordinated water mol-ecules are linked by extensive N-H⋯N, N-H⋯O, O-H⋯N and O-H⋯O hydrogen bonds, forming a three-dimensional network.