Bismuth oxide based electrolytes have been widely studied due to their high oxide ion conductivity. The d-phase of Bi2O3 shows the highest known oxide-ion conductivity of any material, but is only stable over a narrow temperature range. Much research has been carried out on stabilisation of this phase through solid solution formation with rare-earth oxides. While, many of these systems show stabilisation of fcc phases closely related to d-Bi2O3, rhombohedral and hexagonal phases have also been observed and have received much less attention. This proposal seeks to address this through a total scattering study of selected rhombohedral and hexagonal rare-earth doped bismuth oxides. In particular we seek to investigate the preferred anion co-ordinations around the bismuth and dopant cations and the likely O2- diffusion pathways in these systems.