[SrF0.8(OH)0.2]2.526[Mn6O12]: Columnar Rock-Salt Fragments Inside the Todorokite-Type Tunnel Structure
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- 作者：Artem M. Abakumov ; Joke Hadermann ; Gustaaf Van Tendeloo ; Maksim L. Kovba ; Yuri Ya. Skolis ; Svetlana N. Mudretsova ; Evgeny V. Antipov ; Olga S. Volkova ; Aleksandr N. Vasiliev ; Natalia Tristan ; Rü ; di
- 刊名：Chemistry of Materials
- 出版年：2007
- 出版时间：March 6, 2007
- 年：2007
- 卷：19
- 期：5
- 页码：1181 - 1189
- 全文大小：1016K
- 年卷期：v.19,no.5(March 6, 2007)
- ISSN：1520-5002
文摘
A new type of composite structure is described consisting of the todorokite-type [Mn6O12] frameworkwith large square tunnels accommodating columnar fragments of the rock-salt structure. The crystalstructure of the new todorokite-type [SrF0.8(OH)0.2]2.526[Mn6O12] compound is solved from transmissionelectron microscopy, and the structure of its anhydrous form [SrF0.8O0.1]2.526[Mn6O12] is refined fromX-ray powder diffraction data. The [Mn6O12] framework consists of mutually perpendicular walls builtof three edge-sharing rutile-type strings of MnO6 octahedra delimiting large square tunnels with the sizeof 3 × 3 octahedra. The interior space in the tunnels is filled with rock-salt type [Sr(F,OH)]4 columns.The structure can be interpreted as being an incommensurate composite structure with the modulationvector q1 = 
hars/gamma.gif" BORDER=0 >c1* (hars/gamma.gif" BORDER=0 > = 0.63157(3)) parallel to the direction of tunnel propagation. The octahedral tunnelwalls compose subsystem I with a [Mn6O12] composition and a periodicity c1 = 2.84 Å, whereas the[Sr(F,OH)]4 columns belong to subsystem II with a periodicity c1/hars/gamma.gif" BORDER=0 > = 4.49 Å, resulting in a [Sr(F,OH)]4hars/gamma.gif" BORDER=0 >[Mn6O12] composition. [SrF0.8(OH)0.2]2.526[Mn6O12] demonstrates a much larger number of cationsinside the tunnels in comparison with the known synthetic and natural marine todorokites. The [SrF0.8(OH)0.2]2.526[Mn6O12] compound shows a spin-glass behavior below T* 
ntities/ap.gif"> 26 K with a dominantantiferromagnetic correlation.
hars/gamma.gif" BORDER=0 >c1* (hars/gamma.gif" BORDER=0 > = 0.63157(3)) parallel to the direction of tunnel propagation. The octahedral tunnelwalls compose subsystem I with a [Mn6O12] composition and a periodicity c1 = 2.84 Å, whereas the[Sr(F,OH)]4 columns belong to subsystem II with a periodicity c1/hars/gamma.gif" BORDER=0 > = 4.49 Å, resulting in a [Sr(F,OH)]4hars/gamma.gif" BORDER=0 >[Mn6O12] composition. [SrF0.8(OH)0.2]2.526[Mn6O12] demonstrates a much larger number of cationsinside the tunnels in comparison with the known synthetic and natural marine todorokites. The [SrF0.8(OH)0.2]2.526[Mn6O12] compound shows a spin-glass behavior below T* ntities/ap.gif"> 26 K with a dominantantiferromagnetic correlation.