Structure of a mixed oxide is cubic close - packed (c.c.p). The cubic unit cell of mixed oxide is composed of oxide ions. One fourth of the tetrahedral voids are occupied by divalent metal A and the octahedral voids are occupied by a monovalent metal B. The formula of the oxide is:
A2BO2
A2B3O4
AB2O2
AB O2
As we learnt in
No. of atoms(z) for end centered unit cell -
Lattice point: at corners and one pair of opposite face centers.
For end centered cubic, z=2
- wherein
Given that its a c.c.p and unit cell is composed of oxide ions.
So,
Octahedral voids
B = 4
Summing up, the formula is
Option 1)
A2BO2
Incorrect option
Option 2)
A2B3O4
Incorrect option
Option 3)
AB2O2
Correct option
Option 4)
AB O2
Incorrect option
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