EPR of VO2+ in the Mineral Wavellite Al3(OH)3(PO4)2 · 5H2O

Abstract

In wavellites from two different localities EPR spectra of VO2+ ions were detected and analyzed. The most prominent center was axial within the limits of error with g = 1.932, gxx = gyy = 1.948, Azz = 171.8 and Axx = Ayy = 54.7 (A in 10-4 cm). The orientation of the z-axis proves that the Al - OH group with the shortest AI - O bond is substituted by the VO2+ ion. Additional spectra of much lower relative intensity with different orientation of their z-axes can also be assigned to certain Al - O combinations.