Phosphate‐Halide Systems: III, Constitution of Glasses in the System NaPO3,‐LiF

The constitution of glasses in the system NaPO3-LiF with the M/P ratio varying from 1.66 to 1.22 and melted in laboratory air and in dry air has been determined. It has been found that when the glasses are melted in laboratory air and quenched immediately after the components have melted into a liquid, most of the fluorine is retained by the glasses; if, however, the melts are heated further, fluorine is gradually replaced by oxygen. Weight-loss determinations on the glasses in the solid state and on the melts agree with the foregoing conclusions. In dry air very little fluorine is lost from the melts even after 1 hour. Chromatographic and infrared analyses show that glasses retaining fluorine contain considerable amounts of monofluoro-orthophosphate groups; only about half the fluorine is present, however, in this form. The distribution of the remaining fluorine is not known.