PREPARATION AND STRUCTURE OF NIOBIUM TUNG STEN-OXIDES (NB,W)(17)O-47 WITH MIXED-VALENCY

Authors
KRUMEICH F HUSSAIN A BARTSCH C GRUEHN R
Citation
F. Krumeich et al., PREPARATION AND STRUCTURE OF NIOBIUM TUNG STEN-OXIDES (NB,W)(17)O-47 WITH MIXED-VALENCY, Zeitschrift fur anorganische und allgemeine Chemie, 621(5), 1995, pp. 799-806
Citations number
33
Categorie Soggetti
Chemistry Inorganic & Nuclear
Journal title
Zeitschrift fur anorganische und allgemeine Chemie
ISSN journal
00442313 → ACNP
Volume
621
Issue
5
Year of publication
1995
Pages
799 - 806
Database
ISI
SICI code
0044-2313(1995)621:5<799:PASONT>2.0.ZU;2-U
Abstract
The formal substitution of 2Nb(5+) by Nb4+ or W4+, respectively, and W 6+ leads to tungsten niobium oxides (Nb,W)(17)O-47 with mixed valency. The phases Nb8-nW9+nO47 with n = 1 to 5 could be obtained by heating (1250 degrees C) mixtures of NbO2 or WO2, respectively, with Nb2O5 and WO3. The products crystallize with the structure of Nb8W9O47. This is proved by X-ray powder diffraction and transmission electron microsco py. A further decrease of the Nb-content results in two-phase products .