Structural analysis of a series of oxygen-coordinated Al(III) in aluminosilicate minerals by X-ray absorption and NMR spectrometries

Al K X-ray Absorption Near-Edge Structure (XANES) spectra of a series of al uminosilicate minerals were analyzed by DV-X alpha MO method. Aluminosilica te minerals in nature contain various oxygencoordinated Al(III), e.g. four- , five- and six- (1:1), and six-fold. In this study, the Al K XANES spectra of anorthite [CaAl2Si2O8], andalusite [Al2SiO5] and kaolinite [Al2Si2O5(OH )(4)] were measured and analyzed in terms of the electron transition probab ilities. Their coordination structures and bond characters were discussed. The results were also compared with those of NMR measurements.