Figure 1 A view of the mol­ecular structure of the asymmetric unit of the title compound, with partial atom labelling. Displacement ellipsoids are drawn at the 50% probability level. Only half of the diprotonated [H2en]2+ cation, situated about an inversion center, is shown (atoms N5 and C7). The Na+ ion is also situated on an inversion center. The H atoms and water mol­ecules have been omitted for clarity.  [article HTML]