A compound is formed by two elements M and N . The element N forms ccp and atoms of M occupy `(1)/(3)` rd of tetrahedral voids . What is the formula of the compound ?
i) Find the number of tetrahedral voids as number of tetrahedral voids = `2 xx ` number of atoms present in the lattice .
ii) Calculate the number of atoms (or ratio) of elements M and N as a chemical formula represents the number of atoms of different elements presents in a compound .
iii) Derive the formula .

Explanation

Suppose atoms of element N present in ccp = x
Then number of tetrahedral voids = 2x
Since , `(1)/(3)` rd of the tetrahedral voids are occupied by atoms of elements M .
Therefore , number of atoms of element `M = (1)/(3) xx 2x = (2x)/(3)`
Ratio of `M : N = (2x)/(3) : x = 2 : 3`
Hence , formula of the compound = `M_(2)N_(3)` .