Phase relations in the system Na2O· Al2O3-CaO· Al2O3-Al2O3 at 1200°C in air were determined using the quenching method and high-temperature X-ray diffraction. The compound 2Na2O · 3CaO · 5Al2O3, known from the literature, was reformulated as Na2O · CaO · 2Al2O3. A new...