Genotypische Oxidhydrate des Wolframs. Zur Frage der Wolframblauverbindungen

Abstract

Die Reduktion von WO3. H2O und WO3. 2 H2O mit Zink und Salzsäure führt zu blauen, sehr luftempfindlichen Oxidhydraten. Der niedrigste erreichte Reduktionsgrad beträgt 2,65. Durch isobaren Abbau erhält man daraus wasserfreie Wolframblauoxide, deren Strukturen sich von WO3 ableiten lassen. Mit zunehmendem Reduktionsgrad wird die pseudo‐orthorhombische WO3‐Zelle tetragonal und schließlich kubisch (ReO3‐Typ). Es bestehen Analogien zu den reduzierten Wolframoxidhydroxiden WO3‐X(OH)X mit x → 0,5.

Defect and Ordered Tungsten Oxides Encapsulated Inside 2H–WX2(X=S and Se) Fullerene-Related Structures

“…Figures 3a-3c show ED ring patterns obtained from groups of particle Types I and III and the reduced commercially available WO precursor, respectively. While the patterns show some minor differences, the d-spacing information obtained from all of them corresponded closely to the tetragonal modification of WO reported by Glemser et al (26), but not to that reported for either theor -forms of tungsten oxide (27,28). The calculated d-spacings of the three precursors and those reported for the tetragonal modification appear in Table 2.…”

“…The calculated d-spacings of the three precursors and those reported for the tetragonal modification appear in Table 2. The latter, which was produced by thermal decomposition of WO ) 2H O, was indexed according to a cell with a "0.53 nm and c "0.383 nm (26). The main differences between the patterns in Figs.…”

Electrochromism in Anodically Formed Tungsten Oxide Films

“…Copper Ks radiation was used and the scanning rate of 2~ l~ Measured d spacings were compared with the ASTM index values. The data reported by Glemser et al (13,14) were used mainly for the identification of the hydrated oxides.…”

“…Figures 2a, 3a, and 4a, show the x-ray diffraction patterns of the films obtained at different temperatures. The experimental data were compared with the ASTM and Glemser et al (14) d spacings, which are reported in the Tables I and II.…”

“…For the case of hydrated oxides represented as WO~.aq, Hurditch has proposed the formation of blue hydrogen tungsten bronzes of general formula WQ-m (OH)m'aq. The H20 molecules provide H + ions which are reduced at the cathode giving rise to active hydrogen atoms, which form a reduced tungsten blue phase WO3.aq -F mH-> WOa-m(OH)m'aq [4] This tungsten blue phase does not correspond to any of the phases studied by Glemser et al (13,14), who have obtained blue tungsten compounds by reduction of WO8, WO~.H20, and WOs'2H20 by means of nascent hydrogen.…”