Mössbauer effect and X-ray distribution function analysis in complex Na2O–CaO–ZnO–Fe2O3–Al2O3–SiO2 glasses and glass-ceramics

Mössbauer spectroscopy at room temperature was carried out to determine the state of iron ions in complex glasses and glass-ceramics in the SiO2–CaO–ZnO–Na2O–Fe2O3–Al2O3 system. Isomer shift values of the glasses suggest that Fe3+ and Fe2+ are in tetrahedral and octahedral coordination, respectively. The spectrum of the glass-ceramic shows that about 60 wt% total iron is in the magnetite phase. The Fe+3/Fe+2 ratio varies with the total iron oxide content of the glasses, indicating that the vitreous network is more distorted when the iron content is greater. X-ray diffraction measurements were carried out to obtain the radial distribution function (RDF). The interatomic distances for Si–Si and Si–O have been determined. The complex composition of these glasses does not allow the estimation of Al–O and Fe–O distances.