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Superconductors and Oxide Compounds

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Questions and Answers

What is the name of the compound that became superconducting in 1986?

Ln2O3
La2-xBaxCuO4 (correct)
Ln4+
La2-xBaxCuO3

Who discovered the superconducting properties of La2-xBaxCuO4?

Curies and Fermi
Bednorz and Müller (correct)
Newton and Galileo
Einstein and Bohr

What is the year in which the oxide superconductors were discovered?

1988
1986 (correct)
1987
1985

What is the reaction that reduces Ln4+ to Ln2O3?

Reduction with H2.O (C) Signup and view all the answers

What is the general formula of the compound that became superconducting in 1986?

La2-xBaxCuO4 (B) Signup and view all the answers

What is the range of coordination numbers observed in Ln3+ complexes?

3-12 (B) Signup and view all the answers

What is the more common type of coordination number in Ln3+ complexes?

Higher coordination numbers (C) Signup and view all the answers

What is the oxidation state of the central metal atom in Ln3+ complexes?

+3 (C) Signup and view all the answers

What type of metal atom is present in Ln3+ complexes?

Lanthanide metal (B) Signup and view all the answers

What is the relationship between coordination number and the central metal atom in Ln3+ complexes?

The coordination number is directly proportional to the size of the central metal atom (B) Signup and view all the answers

What is the temperature at which Nb3Ge exhibits zero resistivity?

30 K (D) Signup and view all the answers

Which of the following lanthanides is NOT used to prepare divalent oxides through reduction of Ln2O3?

La (A) Signup and view all the answers

What is the structural characteristic of the C-type Ln2O3?

LnO6 units, but not octahedral (C) Signup and view all the answers

At what temperature range are the divalent oxides prepared through reduction of Ln2O3?

800-2000 oC (C) Signup and view all the answers

What is the common method for preparing divalent oxides of Nd, Sm, Eu, and Yb?

Reduction of Ln2O3 with the elemental lanthanide (D) Signup and view all the answers