Structure of glasses in the system Sn-Pb-P-F-O

A quantitative structural model of oxyfluoride glasses in the system Sn-Pb-P-F-O is proposed on the basis of IR, XPS, NMR and Mossbauer spectroscopy. The main structure of the glass is that phosphorus tetrahedra [PO 4-x F x ] (x=0, 1, 2) including P-F bonds connected to each other by intervening Sn(Pb) or SnO(PbO). This gives rise to the network of the -O-P-O-Sn- linkage. Besides, there are Sn(Pb)-F bonds in this structure. The existence of covalent and less polar P-F bonds results in the molecular nature in the structure of the glasses