突出的BaAl4结构类型的s-p结合代表:关于极性金属间网络结构的结构稳定性的案例研究
Ulrich Häussermann1, Shahrad Amerioun, Lars Eriksson
1Department of Inorganic Chemistry, Stockholm University, S-10691 Stockholm, Sweden.
Journal of the American Chemical Society
|April 19, 2002
概括
这项研究研究了具有BaAl4结构的s-p结合化合物,发现了稳定性的14电子规则. 然而,电子缺乏是常见的,而离子大小影响了这些极性金属间的结构变化.
科学领域:
- 固态化学 固态化学
- 材料科学 材料科学 材料科学
- 计算材料科学科学 计算材料科学
背景情况:
- 研究极性金属间结构的形成和原子排列是复杂的.
- BaAl4结构类型 (空间组I4/mmm) 是s-p结合化合物的关键框架.
研究的目的:
- 对具有BaAl4结构类型的s-p结合化合物的结构稳定性进行综合实验和理论研究.
- 探索极地金属间结构的结构形成和原子排列.
主要方法:
- 使用伪电位和平面波基设置的ab initio计算来确定结构参数,结合能和电子结构.
- 使用X射线单晶和粉末衍射的实验合成和结构特征.
主要成果:
- 每个公式单位14个电子的费米级状态密度的伪差距表明BaAl4型化合物的最佳稳定性.
- 实验结果显示,合成的BaAl4型极性金属间金属中经常存在电子缺陷.
- "X"元素的位置偏好受到"色彩能量"和电阳性Ae元件的大小的影响.
- 阴离子大小显著影响近邻距离和聚离子网络 (X4(2-)) 的灵活性.
结论:
- 虽然14电子计数有利于稳定性,但导致电子缺乏的偏差在BaAl4型极性金属间金属中很常见.
- 结构变化,包括单临床扭曲和EuIn4类型的形成,发生的原因是与聚离子子的大小不匹配.
- 这项研究提供了关于极性金属间结构性质关系的见解.
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