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The Polycationic Main Group Element Clusters (As 3 S 5 ) + and (As 3 Se 4 ) + – Syntheses from Chloroaluminate Melts, Crystal Structures, and Vibrational Spectra
Author(s) -
Beck Johannes,
Schlüter Stefan,
Zotov Nicolay
Publication year - 2005
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.200500273
Subject(s) - monoclinic crystal system , chemistry , crystallography , raman spectroscopy , crystal structure , ion , chalcogen , octahedron , infrared spectroscopy , optics , physics , organic chemistry
The reaction of arsenic, arsenic trichloride and AlCl 3 with sulfur or selenium, respectively, in closed glass ampoules at 80 °C leads to melts from which on slow cooling to 50 °C (As 3 S 5 )[AlCl 4 ] and (As 3 Se 4 )[AlCl 4 ] can be obtained in the form of yellow and red crystals. The crystal structures ((As 3 S 5 )[AlCl 4 ]: monoclinic, P 2 1 / m , a = 640.48(4), b = 977.54(7), c = 1146.39(8) pm, β = 104.003(3)°; (As 3 Se 4 )[AlCl 4 ]: monoclinic, C 2/ c , a = 2080.57(2), b = 1251.41(1), c = 1367.68(1) pm, β = 127.969(1)°) consist of nearly regular tetrahedral [AlCl 4 ] − ions and of arsenic‐chalcogen polycations. The structures of the cations can be derived from As 3 E tetrahedra (E = S, Se) with three edges bridged by Se atoms for (As 3 Se 4 ) + and with four edges bridged by S atoms for the C S symmetric (As 3 S 5 ) + . In both structures the ions are arranged in the motif of the CsCl structure type. Infrared und Raman spectra of both compounds show the vibration modes of both kinds of ions in the region 50 – 500 cm −1 . Symmetry analysis and normal mode calculations of the vibrational spectra of (As 3 Se 4 )[AlCl 4 ] confirm the presence of the (As 3 Se 4 ) clusters and the [AlCl 4 ] groups.