Phase equilibria and immiscibility in the TeO2-P2O5 system

The phase equilibria and immiscibility of mutual glass formers up to 50 mol% P₂O₅ have been studied. Phase analysis indicates the formation of three new phases — incongruent melting Te₄P₂O₁₃, Te₂P₂O₉, and a supposed metacompound. Electron microscope investigations established stable and metastable phase separation. The immiscibility confines the tendency to glass formation up to 25.8 mol % P₂O₅. A reliable interpretation in relation to the morphology of liquid-liquid immiscibility and crystallization is considered.