1-Methyl-piperazine-1,4-diium dipicrate.

IN THE CRYSTAL STRUCTURE OF THE TITLE COMPOUND [SYSTEMATIC NAME: 1-methyl-piperazine-1,4-diium bis-(2,4,6-trinitro-phen-ol-ate)], C(5)H(14)N(2) (2+)·2C(6)H(2)N(3)O(7) (-), the ionic components are connected by relatively strong N-H⋯O hydrogen bonds into centrosymmetric six-membered conglomerates, which comprise two dications and four anions. Besides Coulombic inter-actions, only weak C-H⋯O inter-actions and some stacking between picrates (separation between the planes of ca. 3.4†à but only a small overlapping) can be identified between these 'building blocks' of the crystal structure. The piperazine ring adopts a chair conformation with the methyl substituent in the equatorial position. In the picrate anions, the twist angles of the nitro groups depend on their positions relative to the phenolate O atom: it is much smaller for the NO(2) groups para to the C-O(-) group [15.23†(9)and 3.92†(14)°] than for the groups in the ortho positions [28.76†(13)-39.84†(11)°].