XAFS Study of Fe K Edge in Al₂O₃-B₂O₃-Fe₂O₃-Na₂O-SiO₂ Glasses

Abstract

Valence state and local environment of Fe in complex glasses related to the system Al 2 O 3 -B 2 O 3 -Fe2O3-Na2O-SiO2 were studied. In all the glasses, the major fraction of Fe exists as Fe 3+ ions but a minor fraction of Fe 2+ ions especially in the glass with the lowest K=[SiO 2 ]/[B 2 O 3 ] ratio was also present. Average Fe⎯O distance in the first shell is 1.80-1.85 Å and coordination number is 4-6. The intensity due to the second sphere is rather weak demonstrating homogeneous distribution of Fe ions in the glass.