The structures of another class of high-temperature ceramic superconductors are shown below. a. Determine the formula of
Question:
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a. Determine the formula of each of these four superconductors.
b. One of the structural features that appears to be essential for high-temperature superconductivity is the presence of planar sheets of copper and oxygen atoms. As the number of sheets in each unit cell increases, the temperature for the onset of superconductivity increases. Order the four structures from the lowest to highest superconducting temperature.
c. Assign oxidation states to Cu in each structure assuming that Tl exists as Tl3+. The oxidation states of Ca, Ba, and O are assumed to be 12, 12, and 22, respectively.
d. It also appears that copper must display a mixture of oxidation states for a material to exhibit superconductivity. Explain how this occurs in these materials as well as in the superconductor in Exercise 75.
Superconductor in Exercise 75
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Step by Step Answer:
a Structure a Ba 2 Ba inside unit cell Tl 8 corners 1 Tl Cu 4 edges 1 Cu O 6 faces 8 edges 5 O Formu...View the full answer
