Crystal structure of tetra­ethyl­ammonium chloride 3,4,5,6-tetra­fluoro-1,2-di­iodo­benzene

Equimolar qu-anti-ties of tetra-ethyl-ammonium chloride (Et4NCl) and 3,4,5,6-tetra-fluoro-1,2-di-iodo-benzene (o-DITFB or o-C6F4I2) have been co-crystallized in a solution of di-chloro-methane yielding a pure halogen-bonded compound, 3,4,5,6-tetra-fluoro-1,2-di-iodo-benzene-tetra-ethyl ammonium chloride (2/1), Et4N(+)·Cl(-)·2C6F4I2, in the form of translucent needles. [(Et4NCl)(o-C6F4I2)2] packs in the C2/c space group. The asymmetric unit includes one mol-ecule of DITFB, one Et4N(+) cation located on a twofold rotation axis, and one chloride anion also located on a twofold rotation symmetry axis. This compound has an inter-esting halogen-bonding environment surrounding the halide. Here, the chloride anion acts as a tetra-dentate halogen bond acceptor and forms a distorted square-pyramidal geometry, with I⋯Cl(-)⋯I angles of 80.891 (6) and 78.811 (11)°, where two crystallographically distinct iodine atoms form halogen bonds with the chloride anion. Resulting from that square-pyramidal geometry are short contacts between some of the adjacent F atoms. Along the b axis, the halogen-bonding inter-action results in a polymeric network, producing a sheet in which the two closest chloride ions are 7.8931 (6) Å apart. The Et4N(+) cation alternates in columns with the halide ion. The expected short contacts (shorter than the sum of their van der Waals radii) are observed for the halogen bonds [3.2191 (2) and 3.2968 (2) Å], as well as almost linear angles [170.953 (6) and 173.529 (6)°].