Crystal structure of cyclo-tris-(μ-3,4,5,6-tetra-fluoro-o-phenyl-ene-κ(2) C (1):C (2))trimercury-tetra-cyano-ethyl-ene (1/1).

The title compound, [Hg3(C6F4)3]·C6N4, contains one mol-ecule of tetra-cyano-ethyl-ene B per one mol-ecule of mercury macrocycle A, i.e., A•B, and crystallizes in the monoclinic space group C2/c. Macrocycle A and mol-ecule B both occupy special positions on a twofold rotation axis and the inversion centre, respectively. The supra-molecular unit [A•B] is built by the simultaneous coordination of one of the nitrile N atoms of B to the three mercury atoms of the macrocycle A. The Hg⋯N distances range from 2.990 (4) to 3.030 (4) Å and are very close to those observed in the related adducts of the macrocycle A with other nitrile derivatives. The mol-ecule of B is almost perpendicular to the mean plane of the macrocycle A at the dihedral angle of 88.20 (5)°. The donor-acceptor Hg⋯N inter-actions do not affect the C N bond lengths [1.136 (6) and 1.140 (6) Å]. The trans nitrile group of B coordinates to another macrocycle A, forming an infinite mixed-stack [A•B]∞ architecture toward [101]. The remaining N atoms of two nitrile groups of B are not engaged in any donor-acceptor inter-actions. In the crystal, the mixed stacks are held together by inter-molecular C-F⋯C N secondary inter-actions [2.846 (5)-2.925 (5) Å].