EELS FINGERPRINT OF AL-COORDINATION IN SILICATES

Al L(2,3)- and Al K-edges from the minerals Beryl, Orthoclase, Sillimanite, Andalusite and Kyanite have been measured using electron energy-loss spectroscopy (EELS). Peaks in the spectra have been assigned to transitions to empty molecular orbitals in the clusters AlO45- and AlO49- with tetrahedral and octahedral symmetry, respectively. Differences have been identified and the possibility of using these as a fingerprint for Al cation-coordination to oxygen is discussed in light of the results of multiple scattering (MS) calculations.