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

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.