Abstract
Crystals of the title compound, (C5H8N3)3[VO2(C2O4)2]·2.5H2O, a mononuclear VV complex, were obtained by slow evaporation at room temperature of an aqueous solution containing vanadium pentoxide, oxalic acid and 2,6-di-amino-pyridine. The asymmetric unit contains one bis-(oxalato)dioxovanadate(V) anionic complex, three 2,6-di-amino-pyridinium cations and two and a half uncoordinated water mol-ecules. The mononuclear vanadium(V) anions are connected to the organic cations and water mol-ecules through a strong N-H⋯O and O-H⋯O hydrogen-bond network, consolidated by π-π stacking inter-actions, to form a three-dimensional structure.