Structural analysis of amorphous V2O5 by large-angle X-ray scattering

Abstract

An amorphous thin plate of vanadium pentoxide, V₂O₅, prepared by ultrafast quenching from the melt (splat-cooling) has been examined by large-angle X-ray scattering (LAXS) and its structure thereby investigated. The intensities at 450 points within the θ range 2° < θ < 70° were measured at room temperature (22°C). The oxygen coordination around the vanadium atoms is tetrahedral, with an average V—O distance of 1·75 Å. The proposed structure is based on sub-units of three VO₄ tetrahedra sharing corners, the relative orientation of which has been determined. The V₂O₅ formula is retained by following the rule that each tetrahedron shares three corners with other VO₄ tetrahedra. Experimental and theoretical intensity and radial distribution curves have been compared to support the model. A proposal is made concerning the transition of the crystal structure of V₂O₅ to the molten and then amorphous states phases, which are supposed to be strongly structurally correlated.