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Synthesis and Crystal Structure of Te 6 [MCl 6 ] (M = Zr, Hf), Containing a Polymeric Chalcogen Cation (Te 6 2+ ) n
Author(s) -
Baumann Alexander,
Beck Johannes
Publication year - 2004
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.200400285
Subject(s) - orthorhombic crystal system , tellurium , chalcogen , crystallography , octahedron , crystal structure , telluride , materials science , chemistry , inorganic chemistry , organic chemistry
The reaction of tellurium, tellurium tetrachloride, and ZrCl 4 or HfCl 4 , respectively, under the conditions of chemical vapour transport in a temperature gradient 220 → 200 °C yields black crystals of Te 6 [ZrCl 6 ] and Te 6 [HfCl 6 ]. While Te 6 [ZrCl 6 ] is formed almost quantitatively, Te 6 [HfCl 6 ] is always accompanied by neighbored phases such as Te 4 [HfCl 6 ] and Te 8 [HfCl 6 ]. The crystal structures of Te 6 [ZrCl 6 ] (orthorhombic, Pbcm , a = 1095.4(1), b = 1085.2(1), c = 1324.5(1) pm) and Te 6 [HfCl 6 ] ( a = 1094.8(2), b = 1086.3(2), c = 1325.0(2) pm) are isotypic and consist of one‐dimensional polymeric (Te 6 2+ ) n cations and of discrete, only slightly distorted octahedral [MCl 6 ] 2‐ anions (M = Zr, Hf). The cations are build of five membered rings which are connected via single Te atoms to a polymer ‐Te‐Te 5 ‐Te‐Te 5 ‐. Out of the six Te atoms of the asymmetric unit of the chain four atoms exhibit two bonds and two atoms exhibit three bonds. The connecting, threefold coordinated Te atoms of the five membered rings carry formally the positive charges. In consistence with the assumption of the presence of throughout localized bonds eH band structure calculations for Te 6 [ZrCl 6 ] show semiconducting behaviour with a band gap of 1.8 eV.