Two hole centers were detected in natural brazilianite by EPR at X-band and temperatures between 20 and 300 K. For the more intense center a hyperfine splitting (hfs) due to two nonequivalent Al nuclei could be completely analyzed by comparison of the hfs patterns with simulations for 1 ^ A\lA~i ^ 1.4. The orientation of the principle axes of these hfs tensors allowed to assign this hole to a specific oxygen in the lattice. The phosphorus bound to it is evidently exchanged against a lower valency cation, most likely Si . In the second center a hfs splitting due to one Al and one P nucleus was identified. Although a complete analysis of their hfs tensors was not possible, this center could also be assigned to a particular oxygen for which evidently one adjacent Al is exchanged against a divalent ion.
In wavellites from two different localities EPR spectra of V02+ 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 = A = 54.7 (A in 10~4cm). The orientation of the z-axis proves that the Al -OH group with the shortest AI -O bond is substituted by the V02+ ion. Additional spectra of much lower relative intensity with different orientation of their z-axes can also be assigned to certain Al -O combinations.
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