Structure of vitrous phosphates of rare earths

The structure of vitrous poly- and ultraphosphates of rare earths is studied. The results obtained are compared with the known structural data for rare earth crystal phosphates. Using X-ray and IR spectroscopic methods, the structure of vitrous polyphosphates opf lanthanum, neodymium, gadolinium and erbium, and ultraphosphates of neodymium, gadolinium, erbium and lutecium, is investigated. The study testifies to the similarity of structure of all ultraphosphate glasses and to the presence of two types of structures, depending on atomic number of rare earth metal in vitrous polyphosphates