The status of molybdenum ions in the lead dioxide-lead glasses and vitroceramics

Glasses and vitroceramics in the xMoO 3 ·(100 − x)[4PbO 2 ·Pb] system with x = 5-50 mol% MoO 3 were prepared by melt quenching method. The influence of MoO 3 content on optical properties and structure of the 4PbO 2 ·Pb host network was investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman, photofluorescence and X-ray photoelectron (XPS) spectroscopies. The X-ray patterns show the presence of a small amount of Pb 2 MoO 5 crystalline phase in the sample with x = 40 mol% MoO 3 . By increasing of MoO 3 content up to 50 mol% MoO 3 , Pb 2 MoO 5 and tetragonal PbO crystalline phases were detected. Raman data show the bending modes of the O Pb O linkages which allow the intercalation of [PbO 4 ] structural units, isolated [MoO 4 ] and deformed [MoO 6 ] structural units as basic structural units formed by lead and molybdenum atoms. The photofluorescence spectroscopy data shows the transitions of Mo + 5 and Pb 2 + ions. According to the XPS data, the vitroceramic network contains mainly [MoO 4 ] tetrahedral units and small amounts of [MoO 6 ] octahedral units.