[Bi2O2(OH) ](NO3) 的二态性 - - 在100K时有序的Pna结构
Matthias Weil1, Owen P Missen2,3, Stuart J Mills3
1Institute for Chemical Technologies and Analytics, Division of Structural Chemistry, TU Wien, Getreidemarkt 9/E164-05-1, A-1060 Vienna, Austria.
Acta crystallographica. Section E, Crystallographic communications
|February 5, 2024
概括
对二氧化二甲 (III) 氧化酸盐的结构再调查显示,在低温下,从一个无序的晶体结构 (Cmc21) 到一个更低的对称性,有序结构 (Pna21) 的相位过渡.
科学领域:
- 无机化学 无机化学 有机化学
- 晶体学 晶体学是指结晶学.
- 材料科学 材料科学 材料科学
背景情况:
- 二氧化二甲 (III) 酸,[Bi2O2 (OH) ] (NO3),是一种具有材料科学潜在应用的多层甲化合物.
- 之前的结构研究表明了特定的晶体对称性,但在不同温度下潜在的相变并未得到充分探索.
研究的目的:
- 通过单晶X射线衍射,重新研究二氧化二甲 ((III) 氧化酸盐的晶体结构.
- 为了识别和描述在低温下发生的任何结构相位过渡.
- 阐明高温和低温阶段之间的结构差异和相似之处,重点关注离子乱.
主要方法:
- 在不同温度 (173K和100K) 的单晶X射线衍射.
- 对晶体结构的分析和空间组的确定 (Cmc21和Pna21).
- 组-子组对称性分析以了解相位过渡机制.
主要成果:
- 从173 K的空间组Cmc21到100 K的Pna21观察到一个结构相位过渡.
- 与高温Cmc21结构相比,低温Pna21结构的对称性较低.
- 重要的是,Cmc21结构中存在的酸盐离子的方向性障碍在Pna21结构中不存在.
结论:
- 氧化二氧化二甲 (III) 酸的晶体结构在冷却时经历了Klassengleiche相变 (指数2) 从Cmc21到Pna21.
- 这种过渡导致酸盐离子有序排列,消除了在更高温度下观察到的障碍.
- [Bi2O2]2+板的基本分层结构与氧化物和酸盐离子交替,在两个阶段保持一致.
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