title: 1,1-Dimethyl-biguanidium(2+) dinitrate.
abstract: In the crystal structure of the title compound, C(4)H(13)N(5) (2+)·2NO(3) (-), the main inter-molecular inter-actions 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 inter-actions in the crystal structure.
authors.affiliation: Department of Inorganic Chemistry, Faculty of Science, Charles University in Prague, Hlavova 2030, 12843 Prague 2,  Czech Republic.
authors.forename: Michaela
authors.initials: M
authors.lastname: Fridrichová
authors.forename: Ivana
authors.initials: I
authors.lastname: Císařová
authors.forename: Ivan
authors.initials: I
authors.lastname: Němec