Reactivity of T-Nb2O5 or H-Nb2O5 towards V2O5. Synthesis in the solid state and properties of V4Nb18O55

Abstract

Abstract:Using the XRD method a comparative study was performed on the reactivity of commercial T-

A mechanochemical route for the synthesis of VNbO5 and its structural re-investigation using structure solution from powder diffraction data

“…Finally, according to the pattern in Figure 6 and the corresponding Rietveld analysis, the endothermic peak around 940 K observed in the thermogram of the as-mixed equimolar mixture can be attributable to the formation of the tetragonal VNb9O25 phase and V2O5. These products have been also observed for the system milled for 20 hours, evidencing the metastable character of VNbO5 as previously reported by Tabero et al 33 Based on the Rietveld refinement, the amount of formed ternary tetragonal phase (65 wt. %) for both the as-mixed powders and ball milled for 20 h after high temperature thermal treatment is in a good agreement with the value expected on the basis of crystallographically evaluated density 4.4 g/cm 3 , slightly lower than 4.6 g/cm 3 quoted for pure Nb2O5.…”

Thermal analysis and crystal growth of doped Nb2O5

“…The phase diagram constructed on the basis of these results shows correspondingly great agreement with that of the present work. The additional intermediate compounds discovered by Waring and Roth actually have a lower oxygen content and are therefore not part of the examined system[39]. For the example mentioned above one finds e.g.…”

A new ceramic continuous solid solution in the CrSnSbO6–FeSnSbO6 system and some of its properties

“…in [28][29][30][31][32]. Stoichiometric amounts of Fe 2 O 3 , Cr 2 O 3 , SnO 2 and α-Sb 2 O 4 as well as CrSnSbO 6 and FeSnSbO 6 were thoroughly mixed in a mechanical grinder (Pulverisette 2, Fritsch, Germany) and the obtained powder was heated in air at temperatures from the range 600-1200 1C.…”