A spinel is an important class of oxides consisting of two types of metal ions with oxide ions arranged in CCP layers. The normal spinel has 1/8 th of the tetrahedral void occupied by one type of metal and one half of the octahedral voids occupied by another type of metal ions such a spinel is formed by `Zn^(2+), Al^(3+) and O^(2-)` with `Zn^(2+)` in tetrahedral void. Then the simplest formula of that spinel is `Zn_(x)Al_(y)O_(z)`  then `x + y + z` is

Answer

7

Explanation

CCP/FCC Z=4
`O^(-2)` ions in CCP so `O_(4)`

Zn occupies `1/8` of T.V `=1/8 xx 8 = 1, Zn`
At occupies `1/2 xx 4 = 2, 1/2 xx 0,V, Zn_(2)Al_(2)O_(4), x+y +z=7`