Topic summary
Bismuth trioxide
Extracted from the Wikipedia article Bismuth(III) oxide.
Allotropes and preparation
Bismuth trioxide has five crystallographic polymorphs. The room temperature phase, α-Bi2O3 has a monoclinic crystal structure. There are three high temperature phases, a tetragonal β-phase, a body-centred cubic γ-phase, a cubic δ-Bi2O3 phase and an ε-phase.