The ternary system Y2O3−CaO−P2O5 has been examined by DTA, X-ray diffraction, IR and microscopic methods. Its phase diagram has been provided within the composition
range YPO4−Ca3(PO4)2−P2O5. The occurrence of four mixed phosphates: Ca3Y(PO4)3, CaYP3O10, CaY(PO3)5, Ca2Y(PO3)7 has been discovered in the system. Basic X-ray data have been determined for these newly discovered compounds and several
methods of their synthesis developed.
Authors:E. Radomińska, T. Znamierowska, and W. Szuszkiewicz
The system Rb3PO4–Ba3(PO4)2 was investigated by thermoanalytical methods, X-ray powder diffraction, ICP, and FT-IR. On the basis of the obtained results its phase diagram was proposed. For this system with one intermediate compound, BaRbPO4, we found that this compound melts congruently at 1700 °C, exhibits a polymorphic transition at 1195 °C and is high-temperature unstable. Also, the intermediate compound was subject to gradual decomposes to Ba3(PO4)2 (the solid phase) and vaporization (with conversion of phosphorus and rubidium oxides into vapor phase). We also found that Rb3PO4 melts congruently at 1450 °C and shows a polymorphic transition at 1040 °C. Regarding Ba3(PO4)2, we have confirmed that it melts congruently at 1605 °C and exhibits a polymorphic transition at 1360 °C.