1-(4-Fluoro-phen-yl)biguanid-1-ium chloride.

The title compound, C(8)H(11)FN(5) (+)·Cl(-), crystallized with a monoprotonated 1-(4-fluoro-phen-yl)biguanidinium cation and a chloride anion in the asymmetric unit. The biguanidium group is not planar [dihedral angle between the two CN(3) groups = 52.0†(1)°] and is rotated with respect to the phenyl group [τ = 54.3†(3)°]. In the crystal, N-H⋯N hydrogen-bonded centrosymmetric dimers are connected into ribbons, which are further stabilized by N-H⋯Cl interactions, forming a three-dimensional hydrogen-bonded network.