Local Environment of Fe Ions in a 40ZnO · 60B2O3 Glass Matrix

Resumo

The valence state and coordination environment of the Fe ions in a number of Fe-containing zinc borate glasses with the general formula xFe₂O₃–(100–x)[40ZnO · 60B₂O₃] (x = 2.5–10 mol %) have been studied by Mössbauer spectroscopy. The results indicate that all of the glasses contain both Fe²⁺ and Fe³⁺ ions. The percentage of trivalent ions considerably exceeds that of Fe²⁺ ions and the relationship between the Fe²⁺ and Fe³⁺ concentrations is essentially independent of the Fe₂O₃ content in the zinc borate matrix. Most of the Fe³⁺ ions are in tetrahedral coordination, but raising the Fe₂O₃ content to above 5 mol % leads to a gradual increase in the percentage of Fe ions in octahedral coordination.