This study also provides insight as to the different local oxide-ion conduction mechanisms operating in the different phases. The previously measured differences in bulk ionic conductivity for Bi 0.913 V 0.087 O 1.587 and Bi 0.852 V 0.148 O 1.648 (σ ≈ 10 -2 and 10 -3 S cm -1 at 673 K, respectively) now become apparent in terms of variations in the O V environments present in these materials.