(±)-3-Carb­oxy-2-(imidazol-3-ium-1-yl)­propanoate

The title compound, C7H8N2O4, crystallizes as a zwitterion, with mol­ecules organized into mol­ecular sheets via carbox­yl–carboxyl­ate and N+—H⋯carboxyl­ate contacts. These sheets are constructed from translationally related mol­ecules that further link to neighboring motifs via π-stacking [centroid–centroid distance 3.504 (3) Å] and weak C—H⋯O contacts