For the spinel structure `(MgAl_(2)O_(4))`, the correct statement is/are

Options

A. 50% octahedral voids are occupied by `Al^(3+)` ions
B. `Al^(3+)` is equally distributed in tetrahedral voids and octahedral voids
C. Oxide ions occupy ccp lattice
D. 12.5% tetrahedral voids are occupied by `Mg^(2+)` ions

Answer

A, C, D

Explanation

For spinel structure, `O^(2-)` ions form fcc arrangement.
`therefore `Number of `TV=8`, Number of OV=4
Number of `Mg^(2+)` ions`=(1)/(8)xxTV=(1)/(8)xx8=1`
Number of `Al^(3+)` ions`=(1)/(2)xxOV=(1)/(2)xx4=2`.
So, 50% OVs are occupied and 1/8th i.e., 12.5% TVs are occupied.