A New Look at Bonding in Trialuminides: Reinvestigation of TaAl3

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• 作者：Cathie L. Condron ; Gordon J. Miller ; Joel D. Strand ; Sergey L. Bud'ko ; and Paul C. Canfield
• 刊名：Inorganic Chemistry
• 出版年：2003
• 出版时间：December 15, 2003
• 年：2003
• 卷：42
• 期：25
• 页码：8371 - 8376
• 全文大小：155K
• 年卷期：v.42,no.25(December 15, 2003)
• ISSN：1520-510X

文摘

Single crystals of TaAl₃ were grown at high temperatures from an Al-rich, binary solution. TaAl₃ adopts the D0₂₂structure type, space group I4/mmm with a = 3.8412(5) Å, c = 8.5402(17) Å, and Z = 2. The structure type,which is the preferred structure for all group 5 trialuminides and TiAl₃ as well as the high-temperature form ofHfAl₃, is a binary coloring of the face-centered-cubic (fcc) arrangement. The distribution of Ta atoms creates athree-dimensional network of vertex and edge-sharing square pyramids of Al atoms. Temperature-dependent electricalresistivity and magnetic susceptibility measurements are consistent with TaAl₃ being a metallic compound with arelatively low density of states at the Fermi surface. Furthermore, tight-binding electronic structure calculations areutilized to describe the bonding in these compounds and to compare their stability with respect to the alternativefcc-related, e.g., the D0₂₃ (ZrAl₃-type) and the L1₂ (AuCu₃-type), structures. A modified Wade's rule argumentprovides insights into the structural preferences.