Tetra­phenyl­phospho­nium iodide–1,3,5-tri­fluoro-2,4,6-tri­iodo­benzene–methanol (3/4/1)

The crystallization of a 1:1 molar solution of 1,3,5-tri­fluoro-2,4,6-di­iodo­benzene (TFTIB) and tetra­phenyl­phosponium iodide (TPPI) from methanol produced tetra­gonal needles of pure TPPI and tabular pseudo-hexa­gonal truncated bipyramids of the title compound, 3C₂₄H₂₀P⁺·3I⁻·4C₆F₃I₃·CH₄O or (TPPI)₃(TFTIB)₄·MeOH. The asymmetric unit is composed of six TPPI mol­ecules, eight TFTIB mol­ecules and two methanol mol­ecules, overall 16 constituents. The formation of the architecture is essentially guided by a number of C—I...I⁻ halogen bonds (XB), whose lengths are in the range 3.276 (1)–3.625 (1) Å. Layers of supra­molecular polyanions are formed parallel to (10-1) wherein iodide anions function as penta-, tetra- or bidentate XB acceptors. The structure is not far from being P2₁/n, but the centrosymmetry is lost due to a different conformation of a single couple of cations and the small asymmetry in the formed supra­molecular anion. One methanol mol­ecule is hydrogen bonded to an iodide anion, while the second is linked to the first one via an O—H...O contact. This second methanol mol­ecule is more loosely pinned in its position than the first and presents very high anisotropic displacement parameters and a seeming shortening of the C—O bond length. The crystal studied was refined as a perfect inversion twin.