Melaminium glutarate monohydrate

The crystal structure of the title new melaminium salt, 2,4,6‐tri­amino‐1,3,5‐triazin‐1‐ium glutarate monohydrate, C₃H₇N₆⁺·C₅H₇­O₄^?·H₂O, is built up from singly protonated melaminium residues, mono‐dissociated glutarate ions and water mol­ecules. The melaminium residues are interconnected by four N—H?N hydrogen bonds to form chains. These chains of melaminium residues form a stacking structure. The glutarate anions form a hydrogen‐bonded zigzag polymer of the form ?HOOC(CH₂)₃COO?HOOC(CH₂)₃COO?]_n. The oppositely charged moieties, i.e. the melaminium and glutarate chains, form two‐dimensional polymeric sheets. These sheets are interconnected by O—H?O hydrogen bonds between the COO^? moieties and the water mol­ecules, and these hydrogen bonds stabilize the stacking structure.