A comparison of the oxygen evolution upon acid dissolution of Ba_0.6K_0.4BiO₃, with the copper-based oxides LaCuO₃ and La_1.85Sr_0.15CuO₄

Gas chromatography/mass spectrometry was used to analyze the oxygen evolved from Ba0.6K0.4BiO3, LaCuO3 and La1.85Sr0.15CuO4 upon dissolution in normal and 18O-enriched acid. From the 18O/16O ratio we show that the oxide phases are the principal source of evolved oxygen in the copper-containing materials, while more than half of the oxygen is evolved from the solution with Ba0.6K0.4BiO3. The difference may be due to the location of the holes, which appear to be predominantly on the oxygens in the copper-based materials and on the Bi(Bi V) in Ba0.6K0.4BiO3. © 1990.