Electrical properties of the α, β, γ, and δ phases of bismuth sesquioxide

Conductivity measurements have been performed on compressed powder specimens of Bi2O3 in the temperature region 300–800°C. The conductivity in the β, γ, and δ phases is predominantly ionic. Oxide ions are the mobile charge carriers. The disorder in these phases is intrinsic even when the samples are contaminated with Au or Pt. The conductivity in the α phase is predominantly p type. The disorder in the α phase is extrinsic up to the α → δ transition at 729°C. From 650 to 729°C a rapidly increasing contribution of oxygen vacancies to the conductivity is apparent.