Structural studies on alkaline earth vanadate glasses (part 2) - ⁵¹V NMR spectroscopic study -

The structure of alkaline earth vanadate glasses, xMO · (100-x)V₂O₅ (M = Ca, Sr, Ba, x = 30, 40, 45, 50, 55), has been investigated by means of ⁵¹V static and magic angle spinning (MAS) NMR spectroscopies. The ⁵¹V NMR spectral parameters of various constituent vanadate groups contained in the vanadate glasses were determined by the spectrum simulation with reference to those of various crystalline vanadates obtained previously. It was found that the structure of alkaline earth vanadate glasses consists mainly of VO₄-tetrahedra in accordance with authors' previous results based on the IR study. It was deduced that for x = 50 the glass network is mainly constituted of one dimensional (VO₃)_n-single chains, and for x ≤ 45 the decrease of the MO content yields a mixture of the V₂O₅-rich phase constituted of three dimensionally branched VO₄-groups and the MO-rich phase constituted of the VO₅-trigonal bipyramids, followed by the decrease of (VO₃)_n-single chains.