51V magic angle spinning solid state NMR studies of Bi4V2O11 in oxidized and reduced states

The environment of vanadium in alpha-Bi4V2O11 was investigated by V-51 solid state NMR studies. The NMR parameters used for the best-fit simulations show the presence of at least three different sites of vanadium, two tetrahedral and one bipyramidal trigonal (or distorted octahedral). V-51 magic angle spinning NMR spectra obtained at different stages in the reduction of Bi4V2O11 confirm the progressive V(v)-V(iv) reduction. The original upfield shifted signal is attributed to V(v) interacting with paramagnetic V(iv) in Bi4V2O10.66.