文献类型：期刊文献

英文题名：Synthesis and large cell structure of Eu₂Cu_2/3Nb_4/3O₇

作者：Xuan, Y; Liu, R; Jia, YQ

机构：[1]E China Univ Sci & Technol, Dept Chem, Shanghai 200237, Peoples R China

年份：1998

卷号：36

期号：1-4

起止页码：195

外文期刊名：MATERIALS LETTERS

收录：;WOS:【SCI-EXPANDED(收录号:WOS:000074629000038)】；

语种：英文

外文关键词：Eu2Cu2/3Nb4/3O7; synthesis; crystal structure

摘要：A new pyrochlore compound Eu2Cu2/3Nb4/3O7 has been synthesized by the wet chemical method and the crystal structure of the compound has been determined. The crystal structure of Eu2Cu2/3Nb4/3O7 belongs to a tetragonal system and the lattice parameters are a = 1.4672 nm and c = 1.7582 nm, respectively. The assignments for the absorption bands in the infrared spectra of the compound are given. The results of both crystal structure and infrared spectra demonstrate that Eu2Cu2/3Nb4/3O7 is a pyrochlore compound. The experimentally measured density and the calculated density indicate that there are 24 formula units in each unit cell. On the basis of these results and other published results, it is suggested that most pyrochlore compounds with a general formula A'B-2'B-2/3 "O-4/3(7) belong to a tetragonal or a hexagonal system and may possess a large cell structure. Eu2Cu2/3Nb4/3O7 is an insulator and the electric resistivity at room temperature is larger than 10(5) Omega cm. (C) 1998 Elsevier Science B.V. All rights reserved.