1,1-Dimethyl­biguanidium(2+) dinitrate

In the crystal structure of the title compound, C(4)H(13)N(5) (2+)·2NO(3) (−), 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 R (2) (2)(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.