On the Structure of Bismuthsesquioxide: The α, β, γ, and δ‐phase

Abstract The structures of four polymorphs of Bi 2 O 3 were investigated by means of X‐ray and neutron powder diffraction. The position parameters of the oxygen atoms in α‐Bi 2 O 3 were refined. High temperature neutron diffraction shows that a complicated disorder exists in the oxygen sublattice of the fluorite related structure of the solid electrolyte δ‐Bi 2 O 3 . X‐ray diffraction data on metastable β‐Bi 2 O 3 correspond with a distorted fluorites structure with the voids in the oxygen sublattice ordered in the 〈001〉 direction. X‐ray and neutron diffraction data indicate that metastable γ‐Bi 2 O 3 is isomorphous to Bi 12 GeO 20 .