Synthesis and structural characterization of the ternary Zintl phases AE₃Al₂Pn₄ and AE₃Ga₂Pn₄ (AE=Ca, Sr, Ba, Eu; Pn=P, As)

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• 作者：Hua He ; Chauntae Tyson ; Maia Saito ; Svilen Bobev ; ^{bobev@udel.edu}
• 关键词：Crystal structure ; Single-crystal X-ray diffraction ; Electronic structure calculations ; Zintl phases.
• 刊名：Journal of Solid State Chemistry
• 出版年：2012
• 期刊代码：130_00224596
• 类别：ch
• 出版时间：April, 2012
• 卷：188
• 期：Complete
• 页码：59-65
• 文件大小：921 K

摘要

Ten new ternary phosphides and arsenides with empirical formulae AE₃Al₂Pn₄ and AE₃Ga₂Pn₄ (AE=Ca, Sr, Ba, Eu; Pn=P, As) have been synthesized using molten Ga, Al, and Pb fluxes. They have been structurally characterized by single-crystal and powder X-ray diffraction to form with two different structures鈥擟a₃Al₂P₄, Sr₃Al₂As₄, Eu₃Al₂P₄, Eu₃Al₂As₄, Ca₃Ga₂P₄, Sr₃Ga₂P₄, Sr₃Ga₂As₄, and Eu₃Ga₂As₄ crystallize with the Ca₃Al₂As₄ structure type (space group C2/c, Z=4); Ba₃Al₂P₄ and Ba₃Al₂As₄ adopt the Na₃Fe₂S₄ structure type (space group Pnma, Z=4). The polyanions in both structures are made up of TrPn₄ tetrahedra, which share common corners and edges to form layers in the phases with the Ca₃Al₂As₄ structure, and chains in Ba₃Al₂P₄ and Ba₃Al₂As₄ with the Na₃Fe₂S₄ structure type. The valence electron count for all of these compounds follows the Zintl-Klemm rules. Electronic band structure calculations confirm them to be semiconductors.