Evolution and chemical state of oxygen upon acid dissolution of YBa/sub 2/Cu/sub 3/O/sub 6. 98

Gas chromatography/mass spectrometry was used to analyze the oxygen evolved from normal and /sup 18/O enriched YBa/sub 2/Cu/sub 3/O/sub 6.98/ upon dissolution in normal and /sup 18/O enriched acid. From the /sup 18/O//sup 16/O ratio the authors show that the oxide phase is the source of all the evolved oxygen. Their results indicate that some of the lattice oxygens are in a state other than O/sup 2-/, probably O/sup -/ or peroxide. the fact that they are unable to chemically detect peroxide suggests that the radical O/sup -/ could possibly be the species released from the oxide.