Crystal structures of three salts of the tri­phenylsulfonium ion

The crystal structures of three salts of tri­phenyl­sulfonium ion are reported, namely, tri­phenyl­sulfonium triiodide (I), tri­phenyl­sulfonium perchorate (II), tri­phenyl­sulfonium hexa­fluoro­phosphate (III).

The reactions of tri­phenyl­sulfonium chloride ([TPS][Cl]) with various acids in methanol yield the corresponding salts tri­phenyl­sulfonium triiodide, C₁₈H₁₅S⁺·I₃⁻ or [TPS][I₃] (I), tri­phenyl­sulfonium perchlorate, C₁₈H₁₅S⁺·ClO₄⁻ or [TPS][ClO₄] (II), and tri­phenyl­sulfonium hexa­fluoro­phosphate, C₁₈H₁₅S⁺·PF₆⁻ or [TPS][PF₆] (III), as crystalline products. These crystals were structurally characterized by single-crystal X-ray diffraction. In all three compounds, the sulfur atom in the tri­phenyl­sulfonium cation adopts a distorted trigonal–pyramidal geometry. [TPS][I₃] (I) and [TPS][PF₆] (III) both crystallize in the space group P2₁/n, while [TPS][ClO₄] (II) crystallizes in P2₁. The S—C bond lengths are comparable across the three salts, and the S—C—S bond angles are consistently between 102 and 106°. Hirshfeld surface analyses reveal that each structure is dominated by hydrogen-based inter­molecular contacts, supplemented by anion-specific inter­actions such as I⋯H in (I), O⋯H in (II), and F⋯H in (III). These contacts organize the ions into mono-periodic ribbon- or chain-like arrangements. No significant π–π stacking is observed.