Crystal structures of 2,4,6-tri­iodo­benzo­nitrile and 2,4,6-tri­iodo­phenyl isocyanide

The title crystals, C(7)H(2)I(3)N, are isomorphous. Both mol­ecules lie across two crystallographic mirror planes and a twofold axis. The principal supra­molecular inter­action is centric R (2) (2)(10) CN/NC⋯I short contacts involving both ortho I atoms, with two contacts bis­ecting each cyano and iso­cyano group. These form ribbons along [010] and give rise to a planar sheet structure parallel to (100). All pairs of adjacent sheets have centric stacking, a mode not previously reported for sheets of this type. This study completes the series of homo-2,4,6-trihalobenzo­nitriles, in which I atoms give the strongest CN⋯X and NC⋯X inter­actions (X = F, Cl, Br, I).