Crystal structure of Mn2Ln3Sb3O14 (Ln=La, Pr and Nd): A new ordered rhombohedral pyrochlore

被引：20

作者：

Fu, W. T. ^{[1
]}

Ijdo, D. J. W. ^{[1
]}

机构：

[1] Leiden Univ, Leiden Inst Chem, Gorlaeus Labs, NL-2300 RA Leiden, Netherlands

来源：

JOURNAL OF SOLID STATE CHEMISTRY | 2014年 / 213卷

关键词：

Structure determination; Rhombohedral pyrochlore; X-ray diffraction; REFINEMENT;

D O I：

10.1016/j.jssc.2014.02.025

中图分类号：

O61 [无机化学];

学科分类号：

070301 ; 081704 ;

摘要：

Manganese rare earth antimonates with the formula Mn(2)Ln(3)Sb(3)O(14) (Ln=La-Yb and Y) have been prepared and their structures were determined by the Rietveld method using X-ray diffraction data. The compounds with Ln=La, Pr and Nd crystallize in a rhombohedral supercell of the cubic fluorite with the space group R (3) over barm and with the lattice parameters a(h) approximate to root 2a(c) and c(h) approximate to root 2 root 3a(c), where a(c) denotes the lattice constant of the cubic fluorite. The structure is pyrochlore-like but differs from the common cubic pyrochlore A(2)B(2)O(7) in that it consists of fully ordered Mn:Ln in the A sites and Mn:Sb in the B sites with the ratio 1:3. The most interesting feature of Mn(2)Ln(3)Sb(3)O(14) is that the divalent Mn ions have different coordination numbers with oxygen and the Mn(II)O-6 (octahedron) and Mn(II)O-8 (hexagonal bipyramid) alternate along the parent cubic fluorite axes. For medium sized lanthanides, i.e. from Ln=Sm, the rhombohedral phase coexists with the cubic phase and Mn2Y3Sb3O14 is cubic a pyrochlore. (C) 2014 Elsevier Inc. All rights reserved.

引用

页码：165 / 168

页数：4

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