Perovskite-related SrBiO₃ and Sr_0.4K_0.6BiO₃ can both be prepared at high pressure. SrBiO₃ has two BiO₆ octahedral sites, one with bond distances of 2 × 2.281, 2 × 2.317, 2 × 2.321 Å and a second with bond distances of 2 × 2.140, 2 × 2.209, and 2 × 2.123 Å. Sr_0.4K_0.6BiO₃ has a single site with Bi–O distances of 2 × 2.110 and 4 × 2.114 Å. Discuss the origins of these structural differences and predict the differences in low-temperature conductivity you might expect for each material. Calculate the Bi bond valence sum for each site assuming R⁰_Bi–O = 2.094 Å.