Diverse Lanthanide Coordination and Selective Ion Exchange in the Microporous Selenites Na4Ln4(SeO3)7O·nH2O (Ln = Gd, Tb, Dy, Ho, Er, Tm, and Yb)

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• 作者：Teresa M. Eaton ; Ryan A. Groom ; Mark A. Silver ; Thomas E. Albrecht-Schmitt
• 刊名：Crystal Growth & Design
• 出版年：2016
• 出版时间：March 2, 2016
• 年：2016
• 卷：16
• 期：3
• 页码：1453-1457
• 全文大小：349K
• ISSN：1528-7505

文摘

Seven isomorphous alkali metal lanthanide selenites, Na₄Ln₄(SeO₃)₇O·nH₂O (Ln = Gd, Tb, Dy, Ho, Er, Tm, and Yb), exhibiting a new structure type, have been prepared by hydrothermal methods. The four crystallographically unique Ln³⁺ cations within the structure exhibit three different coordination environments that are best described as bicapped trigonal prisms, trigonal dodecahedra, and pentagonal bipyramids. These polyhedra edge- and corner-share to yield diamond-shaped channels that extend along the a axis and are approximately 8.4 Å × 10.5 Å. These channels house alkali metal cations and disordered water molecules. The Ho-analog was chosen for ion-exchange studies that indicate that the Na⁺ cations in the channels can be selectively exchanged for Rb⁺, but ion exchange with other monovalent cations does not occur.