Cation disorder in NaW2O6+δ·nH2−zO post-ion exchange with K, Rb, Sr, and Cs
Cation disorder in NaW2O6+δ·nH2−zO post-ion exchange with K, Rb, Sr, and Cs
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DOI：
10.1016/j.jpcs.2011.02.018
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发表时间：
2011-06
影响因子：
4
通讯作者：
G. Thorogood;B. Kennedy;M. Avdeev;V. Peterson;J. Hanna;V. Luca
中科院分区：
文献类型：
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作者：
G. Thorogood;B. Kennedy;M. Avdeev;V. Peterson;J. Hanna;V. Luca
用热分析、固体核磁共振、实验室X射线和中子衍射等方法研究了缺陷烧绿石NaW 2 O 6 +δ·nH 2 −zO经K、Rb、Sr或Cs离子交换后的结构。中子衍射研究表明，A型阳离子（Na+，K+，Rb+，和/或Cs+）和水分子驻留在111方向的W2 O 6框架中形成的通道内，这些强烈的相互作用。分析结果表明，水和A-型阳离子竞争的空间内的W2 O 6烧绿石框架的隧道，水分子和阳离子的总数是近似恒定的6个样品的调查。阳离子和水之间的相互作用解释了晶格参数对阳离子选择的非线性依赖性。看来材料的离子交换能力将由样品中最初存在的水量控制。
The structure of the defect pyrochlore NaW2O6+δ·nH2−zO after ion exchange with K, Rb, Sr or Cs for Na has been investigated using thermal analysis, solid-state nuclear magnetic resonance, laboratory X-ray and neutron diffraction methods. Neutron diffraction studies show that both the A-type cations (Na+, K+, Rb+, and/or Cs+) and the water molecules reside within the channels that form in the 111 direction of the W2O6framework and that these strongly interact. The analytical results suggest that the water and A-type cations compete for space in the tunnels within the W2O6pyrochlore framework, with the total number of water molecules and cations being approximately constant in the six samples investigated. The interplay between the cations and water explains the non-linear dependence of the a lattice parameter on the choice of cation. It appears that the ion-exchange capacity of the material will be controlled by the amount of water initially present in the sample.