Hy. Cheng et al., Studies of the structure of vanadium species in VAPO-5 molecular sieves via density functional theory computation and Raman spectroscopy, J PHYS CH B, 104(44), 2000, pp. 10293-10297
Based on the density functional theory calculation using B3LYP hybrid metho
d, a distorted square pyramidal (V4+=O)(O-f)(4) unit in a reduced and dehyd
rated VAPO-5 is formed by the vanadium (IV) oxide ion anchored to two neigh
boring 12-membered TO4 rings of the aluminophosphate-5 lattice. By breaking
two V-O-T bonds on one twelve-membered-ring to form another V=O bond, V4can be oxidized to a tetrahedral di-oxo V5+O4 unit. The computed structures
of vanadium oxide species have been confirmed by Raman spectroscopy.