Host Lattice Effect on Paramagnetic Impurity: Single Crystal EPR Study of VO(II)-Doped Biomineral Cadmium Ammonium Phosphate Hexahydrate

Abstract

Single crystal electron paramagnetic resonance studies on VO(II) doped cadmium ammonium phosphate hexahydrate were carried out at room temperature. The paramagnetic impurity VO(II) was found to enter the host lattice both substitutionally and interstitially. The spin Hamiltonian parameter values calculated from crystal rotations for both the locations are; Site1: g∥ = 1.939, g⟂ = 1.992, A∥ = 16.3mT, A⟂ = 7.7mT and site2: g∥ = 1.933, g⟂ = 1.998, A∥ = 16.2mT, A⟂ = 7.7mT. The powder spectra values agree well with the single crystal data. The two sites have been identified as at right angles to each other. The admixture coefficients and other parameter values (κ and P) were evaluated from the spin Hamiltonian parameters. The complex was found to be fairly covalent in nature.

EPR and optical investigation of VO(II) in Zn(C3H3O4)2(H2O)2 single crystals: An interstitial site

“…In a large number of EPR studies on vanadyl ion in various host lattices [2][3][4][5][6][7][8][9][10][11], experiments have shown that the V(IV) ion of VO(II) is surrounded by a distorted octahedron in which the vanadyl bond VQO has a well-defined orientation [12], since the EPR spectrum is very sensitive to the crystalline environment. The behaviour of unpaired electron in VO(II) complexes is dominated by the strong VQO bond.…”