Syntheses and crystal structures of phenyltrimethylammonium salts of hexabromoselenate(IV), [C6H5(CH3)(3)N](2)[SeBr6], and catena-poly[(Di-mu-bromobis{tetrabromotellurate(IV)})-mu-bromine], [C6H5(CH3)(3)N](2n)[Se2Br10 center dot Br-2](n)

The crystal structures of [C6H5(CH3)(3)N](2)[SeBr6] (1) and [C6H5(CH3)(3)N](2n)[Se2Br10. Br-2](n) (2) have been determined by X-ray methods and refined to R = 0.030 and 0.060 for 2834 and 1573 reflections, respectively. Crystals of 1 are monoclinic, space group P2(1)/c with Z = 2 and a = 8.681 (2), b = 10.533(3), c = 14.060(2) Angstrom, beta = 104.26(2)degrees. Crystals of 2 are triclinic, space group P1 with Z = 1 and unit cell dimensions a = 8.698(1), b = 8.931(1), c = 11.563(1) Angstrom, alpha = 94.74(1), beta = 101.87(2), gamma = 90.47(2)degrees. The [SeBr6](2-) octahedron of 1 is centrosymmetric with Se-Br = 2.5740(3), 2.5706(3), 2,5695(3) Angstrom and Br-Se-Br = 90.47(1), 90.13(1), 91.17(1)degrees. The anion of 2 has a dimeric, centrosymmetric Se2Br10 unit, consisting of two edge-sharing SeBr6 octahedra, with one of the axial Br atoms of each octahedron linked to an equivalent Br atom by a Br-2 bridge, so forming a polymeric [Se2Br10. Br-2](2n-)(n) chain. The Se2Br10 unit has Se-Br dimensions 2.3840(22) and 2.4228(23) Angstrom for equatorial terminal, and 2.9428(21) Angstrom for equatorial bridging, and 2.5617(22) and 2.5727(22) Angstrom for axial bonds. The Br-Br-2-Br bridge has Br-Br-2 = 3.0973 (23) Angstrom, Br-Br' = 2.3385(35) Angstrom, Br-Br-Br'= 173.00(19)degrees and Se-Br-Br= 114.23(8)degrees.