Figure 6. Bi2O3 rich regions of Bi2O3—RO3 systems, as determined from hiqh-temperature x-ray diffraction data.
Phases: Mon—monoclinic, C—cubic, ss—solid solution, ?—unknown, Liq— liquid
(A) Bi2O3—CrO3
Compositions formulated from Cr2O3. Diagram shown on CrO3 basis because on calcining, specimens changed in color from green to red, and ? phase is similar to that formed with the hexavalent ions.
a—Unknown composition, apparently pseudotetragonal (similar to the phase in the Bi2O3—MoO3 and Bi2O3—WO3 systems).
b—Phases found at these temps, do not agree entirely with postulated phase boundaries, because system may be pseudobinary.
(B) Bi2O3—MoO3
a—Unknown composition, apparently pseudotetragonal (similar to the phase in the Bi2O3—CrO3 and Bi2O3—WO3 systems).
b—Reversibility demonstrated with high-temp, x ray.
(C) Bi2O3—WO3
a—Unknown composition, apparently pseudotetragonal (similar to the phase in the Bi2O3—CrO3 and Bi2O3—MoO3 systems).
b—Reversibility demonstrated with high-temp, x ray.