Question

In the spinel structure, oxides ions are cubical`-` closest packed whereas `1//8 th` of tetrahedral voids are occupied by `A^(2+)` cation and `1//2` of octahedral voids are occupied by `B^(2+)` cations. The general formula of the compound having spinel structure is `:`
A. `A_(2)B_(2)O_(4)`
B. `AB_(2)O_(4)`
C. `A_(2)B_(4)O_(2)`
D. `A_(4)B_(2)O_(2)`

Answer 1

Correct Answer - B
Effective number of `O^(2-)` in a unit cell `=8xx(1)/(8)+6xx(1)/(2)=4`
Effective number of `A^(2+)` in a unit cell `=8xx(1)/(8)=1`
Effective number of `B^(3+)` in a unit cell `=4xx(1)/(2)=2`
`therefore` General formula `=AB_(2)O_(4)`