Structural Investigations of xV2O5-(100-x)B2O3 Glass Matrix by Spectroscopic Techniques

Abstract

Preparation of glasses of xV2O5-(100-x) B2O3 (21 ≤ x ≤ 41) system for x = 21, 31, 41 mol % have been performed using sol-gel process and studied by employing XRD, FT-IR, EPR and UV-visible techniques. The glassy phase was established by powder XRD patterns. Fourier transform infrared red studies of the amorphous samples revealed the appearance of triangular [BO3/2] and tetrahedral [BO4/2] and V = O units. X-band powder EPR studies exhibit partially resolved isotropic lines at 300 K and well resolved hyperfine structure having a 16 line features (8 parallel lines and 8 perpendicular lines) at 77 K. The assignment of EPR parameters, gxx = gyy = g⊥ > gzz = g|| and Azz = A|| > Axx = Ayy = A⊥ is consistent with ground state 2 B2 which confirms that the tetravalent vanadium (3d 1) exists in the glass matrix as vanadyl ion in tetragonally distorted compressed octahedral symmetry having C4v symmetry. UV-visible absorption spectra of glasses exhibit characteristic two ligand field d-d bands in the tetragonal fields of VO 2+ ions. Using EPR parameters and UV-visible data, various molecular orbital bonding parameters were ascertained.