N‐(2,4‐Dimethoxy­benzyl­idene­amino)­guanidinium dihydrogenphosphate

In the asymmetric unit of the title compound, C₁₀H₁₅N₄O₂⁺·H₂PO₄⁻, there are two protonated amino­guanidinium cations and two dihydrogenphosphate anions. The positive charge on the protonated amidine group is delocalized over the three C—N bonds in a manner similar to that found in guanidinium salts. The amino­guanidinium cations are found to be the E‐isomer structures. Intra­molecular inter­actions of the N—H⋯N type are observed, leading to the formation of five‐membered rings. Extensive networks of O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds stabilize the three‐dimensional network. In the crystal structure, π–π inter­actions between the benzene rings, with a distance of 3.778 (2) Å between the ring centroids, also affect the packing of the mol­ecules.