Hexakis(melaminium) tetrakis(dihydrogenphosphate) monohydrogenphosphate tetrahydrate.

The crystal structure of the new melaminium salt, hexakis(2,4,6-triamino-1,3,5-triazin-1-ium) tetrakis(dihydrogenphosphate) monohydrogenphosphate tetrahydrate, 6C(3)H(7)N(6)(+).4H(2)PO(4)(-).HPO(4)(2-).4H(2)O, is built up from singly protonated melaminium residues, dihydrogenphosphate and monohydrogenphosphate anions, and water molecules. The melaminium residues are interconnected by four N-H...N hydrogen bonds, forming chains along the [001] direction. These chains of melaminium residues form stacks aligned along [100]. The dihydrogenphosphate anions interact with the monohydrogenphosphate anions via the H atoms and, together with hydrogen-bonded dimers of the water molecules, develop layers parallel to the (010) plane. The oppositely charged moieties interact via multiple N-H...O hydrogen bonds that stabilize the stacking structure.