Mössbauer studies on some glasses and crystals in the Na2OFe2O3SiO2 system

TLDR: Mossbauer absorption measurements have been made at room temperature on 57Fe in iron sodium silicate glasses containing 3-15 mol% Fe2O3 and various iron alkali silicate crystals in order to study the state of iron in these glasses as discussed by the authors.

Abstract: Mossbauer absorption measurements have been made at room temperature on 57Fe in iron sodium silicate glasses containing 3–15 mol% Fe2O3 and various iron alkali silicate crystals in order to study the state of iron in these glasses. The spectra of all the glasses gave one doublet with a quadrupole splitting varying from 0.73–0.78 mm s−1, while those of Na2O · Fe2O3 · 4 SiO2 and 5 Na2O · Fe2O3 · 8 SiO2 crystals showed much smaller quadrupole splitting, 0.28 mm s−1 and 0.10 mm s−1, respectively, and an asymmetrical doublet of much narrower linewidth. When sodium was replaced by other alkali metals of larger size, such as K and Cs, in MFeSi2O6 and MFeSi3O8 crystals, the quadrupole splitting became wider and approached to 0.73 mm s−1. Such a variation was not observed for glasses. These results suggest that a larger number of non-identical sites exist in iron sodium silicate glasses than in the corresponding crystals.