在一个扩展的氧化物中,YBaCo2O5和LaBaCo2O5:方形平面Co (I) 的拓性还原
James Seddon1, Emmanuelle Suard, Michael A Hayward
1Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom.
Journal of the American Chemical Society
|February 6, 2010
概括
氧化物YBaCo ((2) O ((5) 和LaBaCo ((2) O ((5) 的拓降解产生了缺离子结构. 一个现场的离子顺序和身份指导了由此产生的金属氧网络和协调环境.
科学领域:
- 固态化学 固态化学
- 材料科学是一种材料科学.
- 无机化学 无机化学 无机化学
背景情况:
- 拓降解是制造缺离子氧化物的一个关键方法.
- 在REBaCo(2) O(5-x) 阶段的A位点阴离子排列会影响它们的结构和磁性特性.
研究的目的:
- 为了研究A位点阴离子排序和同一性直接阴离子空位排序如何在高压降解的氧化物中.
- 为了合成和表征具有不寻常协调环境的新离子缺乏氧化物结构.
主要方法:
- 使用 NaH 降低低温.
- 用X射线衍射进行结构分析.
- 测量磁感应度的测量.
- 可变温度中子衍射.
主要成果:
- 合成了YBaCo ((2) O ((4.5) 和LaBaCo ((2) O ((4.25),表现出不同的离子空位有序结构.
- YBaCo(2)O(4.5) 具有CoO(5) 和CoO(4) 单位,而LaBaCo(2)O(4.25) 则包括CoO(5),CoO(4),和CoO(4) 方形平面单位.
- 这两种化合物都显示出分别低于280K和325K的反铁磁排序,其中LaBaCo(2)O(4.25) 显示出Co(I) 中心的证据.
结论:
- A位点阳离子 (Y3+和La3+) 的身份和排序决定了这些氧化物中阳离子空位的排序结构.
- 有序的A位点提供了一条控制离子空位的途径,在拓法降解中进行排序.
- 这一策略使得能够制备具有独特过渡金属协调几何学的新型金属氧框架.
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