Fig. 7. Fourier transforms of EXAFS spectra and curve-fits of representative samples. The upper inset is the original χ(k) data, the lower are the transform moduli of the data, fit, and difference, and (inverted) the contributions of the individual neighbor shells. The curve-fits included the oxo, two equatorial O, a P/Si/Al at 3.1 Å (P wave), and the multiple scattering oxocontribution (MS oxo).