A STUDY OF SILICON ELNES IN NESOSILICATES

Si L2,3-absorption edges have been collected using EELS from four nesosilicates; Forsterite, Fayalite, Phenacite and Willemite. Nesosilicates, also known as orthosilicates or island silicates, are the simplest materials to be found in the silicate mineral class, consisting of isolated tetrahedral SiO4 groups. While many features in energy-loss spectra are common to all of the materials, remarkable extra intensity was observed for Forsterite. This appears to arise from distortion of the SiO4 tetrahedron; a hypothesis supported by XANES calculations. The concept of a simple fingerprint in near-edge structure analysis is questioned.