Vanadium-51 MAS and Static NMR Studies of the Binary V2O5−WO3 System

Abstract

Solid-state NMR spectra showing single-quantum excitation of the vanadium-51 (I = 7/2) central and six satellite transitions were obtained for polycrystalline V2O5 and x%V2O5−(100 − x%)WO3 (10 mol % ≤ x ≤ 40 mol %) solids by magic angle spinning (MAS) and static NMR spectroscopies. All MAS spectra show full spinning sideband manifolds resulting from incomplete averaging of the chemical shift and quadrupolar interaction anisotropies. Chemical shift parameters (δiso, δaniso, ηcs) and quadrupolar parameters (CQ, ηQ) were obtained by simulation of both MAS and static spectra. A single vanadium site was observed in the nominally 40 mol % V2O5−60 mol % WO3 and 30 mol % V2O5−70 mol % WO3 compositions. Interpretation of NMR spectral parameters suggests that the vanadium in this single site resides in a square pyramid-like oxygen coordination environment. Three sites were observed for the nominally 20 mol % V2O5−80 mol % WO3 and 10 mol % V2O5−90 mol % WO3 compositions. The spectral parameters for the three sites a...