L-Histidinium dipicrate dihydrate

In the title mol­ecular salt, C₆H₁₁N₃O₂²⁺·2C₆H₂N₃O₇⁻·2H₂O, the histidine mol­ecule exists as a histidinium dication, being protonated at the N atom of the imidazole ring. The charges are balanced by two picrate anions and the compound crystallizes as a dihydrate. In the crystal, the components are linked via N—H...O and O—H...O hydrogen bonds and weak C—H...O inter­actions, forming a three-dimensional supermolecular structure.