4,4'-(Propane-1,3-di-yl)dipyridinium tetra-chloridonickelate(II).

The title compound, (C(13)H(16)N(2))[NiCl(4)] or (H(2)bpp)·NiCl(4) [bpp is 1,3-bis-(4-pyrid-yl)propane], is isostructural with its already reported Cu, Zn and Hg analogues. The structure consists of a doubly charged (H(2)bpp)(2+) cation and a tetra-hedral [NiCl(4)](2-) dianion. Both pyridyl N atoms are protonated and form a (H(2)bpp)(2+) cation which adopts an anti-anti conformation with a dihedral angle of 6.287 (7)° between the pyridyl rings. The two pyridyl N atoms are both involved in strong N-H⋯Cl hydrogen bonds, which link both units into a dimer.