Structure and properties of Tl2Nb2O6+x phases with the pyrochlore structure

被引:10
|
作者
Uma, S
Kodialam, S
Yokochi, A
Khosrovani, N
Subramanian, MA
Sleight, AW
机构
[1] Oregon State Univ, Dept Chem, Corvallis, OR 97331 USA
[2] Dupont Co, Cent Res & Dev, Expt Stn, Wilmington, DE 19880 USA
基金
美国国家科学基金会;
关键词
thallium niobate; structure; composition;
D O I
10.1006/jssc.2000.8937
中图分类号
O61 [无机化学];
学科分类号
070301 ; 081704 ;
摘要
Phases with the cubic pyrochlore structure and the composition Tl2Nb2O6+x were prepared under various oxygen pressures. Rietveld refinements of neutron powder diffraction data showed 10.674 Angstrom for x = 0.11, a = 10.637 Angstrom for x = 0,44, and a = 10.627 Angstrom for x = 0.64. Reflections forbidden by spherical atoms in ideal positions are observed at x = 0.11, and these can be attributed to an anisotropic thermal displacement parameter for Tl. Despite the Tl(I)/Tl(III) mixed valency, these phases show a high electrical resistivity. (C) 2000 Academic Press.
引用
收藏
页码:225 / 228
页数:4
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