rac-3-exo-Ammonio-7-anti-carb­oxy­tricyclo­[2.2.1.0.^2,6]heptane-3-endo-carboxyl­ate monohydrate

The racemic title compound, C₉H₁₁NO₄·H₂O, a tricyclic rearranged amino­norbornane dicarb­oxy­lic acid, is a conformationally rigid analogue of glutamic acid and exists as an ammonium-carboxyl­ate zwitterion, with the bridghead carb­oxy­lic acid group anti-related. In the crystal, N—H...O and O—H...O hydrogen bonds involving the ammonium, carb­oxy­lic acid and water donor groups with both water and carboxyl O-atom acceptors give a three-dimensional framework structure.