Materials containing the elements Y, Ba, Cu, and O that are superconductors (electrical resistance equals zero) at temperatures above that of liquid nitrogen were recently discovered. The structures of these materials are based on the perovskite structure. Were they to have the ideal perovskite structure, the superconductors would have the structure shown in part (a) of the accompanying figure.

a. What is the formula of this ideal perovskite material?
b. How is this structure related to the perovskite structure discussed in Exercise 74? These materials, however, do not act as superconductors unless they are deficient in oxygen. The structure of the actual superconducting phase appears to be that shown in part (b) of the figure.
c. What is the formula of this material?

Transcribed Image Text:

Barium Oxygen Yttrium (a) Ideal perovskite structure (b) Actual structure of