Compressed copper(2+) ions in Bi4V2O11 bismuth oxide matrix. 1. EPR and UV-visible study

BICUVOX.x (Bi[sub 2]V[sub 1-x]Cu[sub x]O[sub 5.5-1.5x]) prepared with different atomic ratios Cu/V and calcined under a dry air at 1093 K have been characterized by electron paramagnetic resonance (EPR). The inverted g anisotropy values of the copper(II) ions EPR signal (g[sub perpendicular] > g[sub parallel]) can be interpreted by an octahedral symmetry strongly distorted with a compression of oxygen atoms along the apical direction. These results have been confirmed by UV-visible spectroscopy. 29 refs., 4 figs., 1 tab.