Modulated and Disordered Phases in the System LiCdVO4-LiCd4(VO4)3
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- 作者：E. Gaudin ; H. Ben Yahia ; F. J. Zú ; ñ ; iga ; J. M. Pé ; rez-Mato ; and J. Darriet
- 刊名：Chemistry of Materials
- 出版年：2005
- 出版时间：May 3, 2005
- 年：2005
- 卷：17
- 期：9
- 页码：2436 - 2447
- 全文大小：440K
- 年卷期：v.17,no.9(May 3, 2005)
- ISSN：1520-5002
文摘
A solid solution (1 - x)LiCdVO4 - xLi1/3Cd1/3MG SRC="/images/entities/square.gif">1/3CdVO4 has been observed for 0 
images/entities/le.gif"> x images/entities/le.gif"> 1. From thecell parameters evolution, two domains of the solid solution have been distinguished with a discontinuityat x images/entities/ap.gif"> 0.6. The first one for 0 images/entities/le.gif"> x images/entities/le.gif"> 0.6 corresponds to the LiCdVO4 substructure of the Na2CrO4-type.For 0.75 images/entities/le.gif"> x images/entities/le.gif"> 1 satellite peaks are observed which correspond to a modulated structure. The firstend-member LiCdVO4 (x = 0) crystallizes in Cmcm space group with a = 5.911, b = 8.975, and c =6.513 Å. The structure consists of infinite edge-sharing chains of [CdO6] octahedra linked together by[VO4] tetrahedra and [LiO4] tetrahedra. According to the general formula Li1-2x/3Cdx/3images/entities/square.gif">x/3CdVO4 of thesolid solution, when x increases cadmium replaces lithium in the [LiO4] tetrahedra leading to [(Li/Cd/images/entities/square.gif">)O4] disordered tetrahedra. All the phases in the domain 0.7 images/entities/le.gif"> x images/entities/le.gif"> 1 are one-dimensionally modulatedwith wavevector q = images/gifchars/gamma.gif" BORDER=0 >c* and images/gifchars/gamma.gif" BORDER=0 > values of 0.75, 0.733, and 0.722 for x = 3/4, 6/7, and 9/10, respectively.The superspace group is Xmcm(00images/gifchars/gamma.gif" BORDER=0 >) where X stands for (1/2, 1/2, 0, 1/2) centering. The main structuralresult is a strong occupation modulation of lithium and cadmium in the tetrahedral site.