HIGH-RESOLUTION SI AND P K-EDGE AND L-EDGE XANES SPECTRA OF CRYSTALLINE SIP2OM AND AMORPHOUS SIO2-P2O5

Si and P K- and L-edge XANES spectra of crystalline SiP2O7 (c-SiP2O7) and amorphous SiO2-P2O5 (a-SiO2-P2O5) are reported using synchrotron r adiation and interpreted using molecular orbital considerations. The S i spectra are consistent with [6]Si in c-SiP2O7 and with [4]Si in a-Si O2-P2O5 (25 mol% P2O5). The resolution of near-edge features in the Si L-edge spectrum of the crystalline material is unprecedented. These sp ectra show definitively that Si XANES spectroscopy is a powerful techn ique for determining [4]Si and [6]Si in amorphous samples.