2,4-Diamino-6-methyl-1,3,5-triazin-1-ium chloride

In the title compound, C4H8N5 +·Cl−, a two-dimensional layer packing network is observed in which every chloride anion links three adjacent 2,4-diamino-6-methyl-1,3,5-triazin-1-ium cations by N—H⋯Cl hydrogen-bonding interactions, forming 12-membered and eight-membered hydrogen-bonded rings with graph-set motifs R 4 4(12) and R 3 3(8), respectively. In addition, N—H⋯N hydrogen bonds are found between adjacent cations, forming another type of eight-membered [R 2 2(8)] hydrogen-bonded ring.

The molecular structure of (I) is illustrated in Fig. 1. The mean deviation from a least-squares plane for all the non-hydrogen atoms of the cations is 0.0039 (1) Å, while that for all the non-hydrogen atoms of (I) including the chloride anion is 0.0041 (1) Å. It is interesting to note that every chloride anion links three adjacent 2,4-diamino-6-methyl-1,3,5-triazin-1-ium cations by N-H···Cl hydrogen bonding interactions forming two kinds of twelve-membered [R 4 4 (12)] and eight-membered [R 3 3 (8)] hydrogen-bonded rings. In addition, N-H···N hydrogen bonding interactions are found between nitrogen atoms N1, N4 and N2, N5 from neighbouring cations, respectively, forming another type of eight-membered [R 2 2 (8)] hydrogenbonded rings. With the help of above-mentioned N-H···N and N-H···Cl hydrogen bonds, a two-dimensional layer packing network is finally constituted (Fig. 2).

Experimental
The title compound was purchased directly from Kangmanlin Co. in China and the colourless single crystals of (I) suitable for X-ray diffraction determination were obtained from a mixture of water and ethanol in a ration of 1:3 (v/v) by slow evaporation at room temperature in air for one week.

Refinement
The H atoms bonded to carbon atoms were placed in geometrically idealized positions and refined as riding with C-H = 0.96 Å and U iso (H) = 1.5U eq (C). The H atom bonded to nitrogen atom was located in the difference synthesis and were refined isotropically.
supplementary materials sup-2 Figures   Fig. 1. The molecular structure of the title compound with the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.

Special details
Experimental. The structure was solved by direct methods (Bruker, 2007) and successive difference Fourier syntheses.
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating Rfactors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.