1-Benzyl-2-dimethyl-amino-3-methyl-3,4,5,6-tetra-hydro-pyrimidin-1-ium bromide.

In the title molecular salt, C(14)H(22)N(3) (+)·Br(-), the ring incorporating the guanidinium grouping exhibits a half-chair conformation and the dihedral angle between the N-C-N and C-C-C planes is 55.0 (3)°. The C-N bond lengths in the central CN(3) unit are 1.333 (4), 1.338 (3) and 1.341 (4) Å, indicating partial double-bond character. The central C atom is bonded to the three N atoms in a nearly ideal trigonal-planar geometry and the positive charge is delocalized in the CN(3) plane. The distances between the N atom and the terminal methyl C atoms [1.453 (4)-1.461 (4) Å] are all close to a typical single C-N bond length.