User:OrganoMetallurgy/Drafts/Barium bismuthate

= non-chembox sections = Barium bismuthate(III)(V), BaBiO3, is a mixed valence semiconductive oxide with a perovskite structure which becomes superconductive at low temperatures when suitably hole doped.

Properties
Semiconductive Losses some oxygen at high temperatures.

Crystal structure
BaBiO3 is a perovskite, there are two distinct bismuth sites It is monoclinic, space group I2/m at room temperature. At temperatures between 430 and 820 K it is rhombohedral with the space group R3, above 820 K it is cubic, space group Fm3m. Below 140 K it is monoclinic with the space group P21/n.

Synthesis
Electrocrystallization Melt and anneal under high oxygen pressure

Potassium barium bismuth oxide (Ba1-xKxBiO3)
Potassium barium bismuth oxide is a superconductor from x ≈ 0.3 to 0.45 the maximum Tc is around 32 K at the approximate composition Ba0.6K0.4BiO3. The superconductive phase is cubic, space group Fm3m, at room temperature, and tetragonal, space group I4/mcm, at low temperatures. The different bismuth sites become more equivalent?/disordered?/less distinct with increasing hole doping.

BaPb1-xBixO3
See the article of barium plumbate for more information. BaPb1-xBixO3 is a superconductor in the composition range x = 0.15 to 0.30 with a maximum Tc of ~12 K at x ≈ 0.25