The Cube‐Shaped Main Group Element Clusters (Bi4S4)4+ and (Bi4Se4)4+ ‐ Synthesis from Chloroaluminate Melts, Crystal Structures and Vibrational Spectra

Abstract

AbstractThe reaction of bismuth and bismuth trichloride with sulfur or selenium, respectively, in a AlCl3/NaCl melt at 130 °C leads to (Bi4S4)[AlCl4]4 1 and (Bi4Se4)[AlCl4]4 2 in the form of red and amber colored crystals. Both crystallize isotypically in the tetragonal space group $I{\bar 4}$ with the lattice constants a = 1181.60(2), c = 1104.75(2) pm for 1 and a = 1199.32(2), c = 1118.64(3) pm for 2. Besides the nearly regular tetrahedral [AlCl4]‐ ions the structures contain (Bi4S4)4+ and (Bi4Se4)4+ cations. These ions are actually of crystallographic S4 symmetry but deviate only slightly from the ideal cubic symmetry. Bi and chalcogen atoms occupy alternatingly the corners of the cubes. 1 and 2 are isotypical to the already known (Bi4Te4)[AlCl4]4, so the series of the cube‐shaped (Bi4E4)4+ ions (E = S, Se, Te) is now complete. Infrared und Raman spectra of 1 und 2 show the vibration modes of both kinds of ions in the region 50 ‐ 600 cm‐1. Symmetry analysis and normal mode calculations of the vibrational spectra confirm the local symmetry of the (Bi4E4) clusters and the [AlCl4] groups.