Study of the Reaction of Ba2YCu3Oy with Air at Room Temperature

Abstract
The copper oxide Ba2YCu3O y (BYCO) reacted with moisture at room temperature when the compound with y=6.45-6.50 was annealed at low temperatures. Water molecules were considered to be incorporated into the vacant sites of BYCO. This reaction was strongly influenced by the synthesis temperature of BYCO, annealing temperature and oxygen numbers of annealed specimens. It is proposed that this reaction is responsible for the 2a superstructure of the annealed BYCO.