1,1-Dimethyl­biguanidium(2+) dinitrate

In the crystal structure of the title compound, C₄H₁₃N₅²⁺·2NO₃⁻, the main inter­molecular inter­actions are the N—H...O hydrogen bonds between the cationic amino groups and the O atoms of the nitrate ions. All amino H atoms and nitrate O atoms are involved in the three-dimensional hydrogen-bond network. There are two graph-set motifs R₂²(8), which include the amino groups connected to the N atoms in the biguanide 3-, 4- and 5-positions, and the O atoms of a nitrate ion. They are extended along the a axis. An O atom of the second nitrate ion is involved in a graph-set motif C(4) that is a part of a helix-like N—H...O...H—N—H...O... chain oriented along the b axis. There are also two weak C—H...O inter­actions in the crystal structure.