[en] The temperatures at which different phases occur in Bi₈Pb₅O_1.7 were determined using room temperature and high temperature x-ray diffraction in combination with differential thermal analysis. These temperatures largely depend on the thermal history of the sample examined. When the room temperature β2-Bi₈Pb₅O_1.7 is re-heated, the relationship of the phases, and their respective temperatures are: below 420 deg C, pure β₂-Bi₈Pb₅O_1.7; 420-460 deg C, coexistence of the β₂-phase and intermediate Φ-phase; 460-590 deg C, the mixed-Φ-phase; 590-615 deg C, a mixture of the Φ-phase and the β-phase; above 615 deg C, single β-phase. On cooling, the high temperature β-phase transfers directly to the β₂-phase in the temperature range 590- 615 deg C. Copyright (1998) Australasian Ceramic Society