A mineral consists of a cubic close-packed structure formed by `O^(2-)` ions where half the octahedral voids are occupied by `Al^(3+)` and one eighth of the tetrahedral voids are occupied by `Mn^(2+)`. The chemical formula of the mineral is

Options

A. `Mn_(3)Al_(2)O_(6)`
B. `MnAl_(2)O_(4)`
C. `MnAl_(4)O_(7)`
D. `Mn_(2)Al_(2)O_(5)`

Answer

B

Explanation

No of `O^(-2)` per unit cell `=8xx(1)/(8)+6xx(1)/(2)=4`
No of `Al^(+3)` per unit cell `=4xx(1)/(2)=2`
No of `Mn^(+2)` per unit cell `=8xx(1)/(2)=1`
`MnAl_(2)O_(4)`