Al7Te10 — das erste Chalcogenid mit zweiwertigem Aluminium / Al7Te10 — the First Chalcogenide of Divalent Aluminum
Open Access
- 1 May 1987
- journal article
- Published by Walter de Gruyter GmbH in Zeitschrift für Naturforschung B
- Vol. 42 (5) , 557-564
- https://doi.org/10.1515/znb-1987-0508
Abstract
Al7Te10 is prepared from a melt of the elements in stoichiometric amounts in a corundum crucible contained in a sealed quartz ampoule. The ruby red cube shaped crystals are stable below 840 K. The structure of Al7Te10 (R32-D3 7 a = 1439.5 pm, c = 1793.2 pm, Z = 6, R = 0.03) is a distorted defect variant of a tetrahedral arrangement of the 4H-polytype. The central unit, a double barrelane [Te4Al4-Al4Te4], contains an Al -Al bond of 260 pm, which is somewhat longer (n = 0.83) than an expected single bond (250 pm, n = 1). This homopolar bond disturbs the electrostatically favorable (Al-Te-)n sequence in the structure which is compensated by the occurrence of four-membered Al2Te2 rings. Al7Te10 is a Zintl phase according to 1/2{[Al2+-Al2+][Al3+]12[Te2-]20} and exhibits semiconducting and diamagnetic behaviour.Keywords
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