A NEW TUNGSTEN-OXIDE WITH 3D TUNNELS - WO3 WITH THE PYROCHLORE-TYPE STRUCTURE

被引：52

作者：

COUCOU, A

FIGLARZ, M

机构：

[1] CNRS, France

来源：

SOLID STATE IONICS | 1988年 / 28卷

关键词：

Chemical Reactions--Ion Exchange - Crystals--Structure - Oxides--Synthesis;

D O I：

10.1016/0167-2738(88)90457-2

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

A new form of WO3 with a pyrochlore-type structure has been discovered. This new oxide is prepared in three steps. First, pyrochlore-type ammonium tungstates [(NH4)2O]xW2O6,x0.5, are prepared by thermal treatment of ammonium tungstate (NH4)10W12O41&middot5H2O in acidic solution of ethylene glycol. Pyrochlore hydrated oxides, W2O6&middotxH2O, are then obtained by ion exchange in acidic aqueous solutions. Dehydration of these hydrates at about 100°C leads to pyrochlore WO3; this oxide behaves as a divariant system toward water. A structural study of this oxide was carried out from X-ray powder diffraction data, showing that WO3 has a cubic pyrochlore structure with space group Fd3m and a=10.270(3) angstrom. The zeolitic water molecules are located in 8b positions.

引用

页码：1762 / 1765

页数：4