Triphenylselenonium iodide

The title compound, Ph3SeI or C18H15Se+. I-, forms an ionic solid comprised of centrosymmetric dimers, in which two Ph3Se+ ions are bridged by two I- ions. The coordination about the Se-IV centers can be described as either a twofold capped trigonal pyramid or a distorted pseudo-octahedron, with the selenium lone pair occupying the sixth position. Selected structural param eters are: Se-C 1.926(4), 1.929(4) and 1.944(4) Angstrom, Se ... I 3.722(1) and 4.153 (1) Angstrom, C-Se-C 100.21 (15), 102.51 (15) and 98.62 (16)degr ees, and C-Se ... I 84.4 (1), 166.5 (1), 92.7 (1), 94.3 (1), 86.2 (1) and 1 61.4 (1)degrees.