Di-μ-chlorido-bis{[2-(benzyliminomethyl)pyridine-κ2N,N′]chloridomercury(II)} dichloridomercury(II)

The HgII ion in the title centrosymmetric dinuclear complex, [Hg2Cl4(C13H12N2)2]·[HgCl2], adopts a distorted square-pyramidal geometry, being coordinated by the bis-chelating N-heterocyclic ligand, two bridging Cl atoms and one terminal Cl atom. One of the bridging Hg—Cl bonds [2.8428 (11) A] is significantly longer than the other [2.5327 (10) A]. In the crystal, there are weak π–π inter­actions [centroid–centroid distance = 3.630 (3) A] between the aromatic rings of the discrete units. The HgCl2 adduct molecule is located on an inversion centre and has an Hg—Cl bond length of 2.2875 (11) A.