Abstract
In the title hydrated molecular salt, (C3H5N2)[Cr(C2O4)(2-)(H2O)(2)]center dot 2H(2)O, the complete cation is generated by a crystallographic twofold rotation axis, with one C atom lying on the rotation axis. The complete anion is generated by crystallographic inversion symmetry (Cr III site symmetry 1), to generate a slightly distorted CrO6 octahedron with trans water molecules and chelating oxalate dianions. The oxalate ion is almost planar (r.m.s. deviation = 0.017 angstrom) and the fivemembered chelate ring is a shallow envelope with the metal ion displaced by 0.126 (1) angstrom from the ligand atoms. The crystal structure features O-H center dot center dot center dot O, N-H center dot center dot center dot O and C-H center dot center dot center dot O hydrogen bonds, which link the components into a threedimensional network.