Hydroxonium 1-ammonioethylidene-1,1-bisphosphonate

The title compound, H3O+·C2H8NO6P2 , contains a disordered H3O+ cation and an NH3C(CH3)(PO3H)2 anion. The three H atoms of the H3O+ cation are statistically distributed over four positions with occupancies of 0.75, resulting in a pseudo tetrahedron. Multiple N—H...O and O—H...O hydrogen bonds generate an intricate three-dimensional network.