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Synthesis and Crystal Structure of (Sb 2 Te 2 )[AlCl 4 ], a Compound Containing a Heteroatomic Polymeric Cation (Sb 2 Te 2 + ) n
Author(s) -
Beck Johannes,
Schlüter Stefan
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.200400427
Subject(s) - isostructural , antimony , crystallography , triclinic crystal system , chemistry , tellurium , crystal structure , atom (system on chip) , covalent bond , cationic polymerization , formula unit , inorganic chemistry , polymer chemistry , organic chemistry , computer science , embedded system
The reaction of tellurium, antimony, antimony trichloride, sodium chloride, and an excess of aluminium trichloride in a closed evacuated glass ampoule yields dark red crystals of (Sb 2 Te 2 )[AlCl 4 ]. During the reaction a melt is formed from which needle shaped crystals of the title compound grow on sublimating off the volatile AlCl 3 at 130 °C. Energy dispersive X‐ray emission analysis showed the 1:1 ratio of Sb:Te. The crystal structure analysis (triclinic, P 1¯, a = 949.30(2), b = 1348.24(3), c = 1804.97(5) pm, α = 78.983(2), β = 88.060(1), γ = 88.444(1)°, V = 2239.65(9)·10 6 pm 3 , Z = 8) shows that the structure is built of almost regular tetrahedral [AlCl 4 ] ‐ anions and of one‐dimensional polymeric (Sb 2 Te 2 + ) n cations. The assignment of Sb and Te atoms to the respective atom positions of the cations was performed by an analysis of the occupation factors, a reasonable electron and charge distribution, and by the analysis of the cation‐anion interactions. The unit cell contains two symmetrically independent but almost isostructural cations which form strands made up of four‐membered stacked Sb 2 Te 2 rings. These rings are connected with their neighboured rings alternatingly via two, three, and four covalent bonds. Predominantly Sb‐Te bonds are present, in smaller degree Sb‐Sb bonds, while Te‐Te bonds are not observed. The cationic strands can be interpreted by the Zintl concept in the connectivity of the different atom types and the resulting charges.