A compound is formed by two elements M and N. The element N forms ccp and atoms of M occupy 1/3rd of tetrahedral voids. What is the formula of the compound?

Q 1.16:A compound is formed by two elements M and N. The element N forms ccp and atoms of M occupy 1/3rd of tetrahedral voids. What is the formula of the compound?

Solution:

Let number of  atoms of the element N = n

Number of tetrahedral voids = 2 × number of atoms in close packaging

Therefore

Number of tetrahedral voids = 2n

It is given that the atoms of element M occupy 1/3rd of tetrahedral voids.

So that the number of atoms of M is = (1/3) × 2n

                                                    =(2/3)n

Ratio of the number of atoms of M and N

   

Multiply by 3 and divide by n we get  

      M:N = 2:3

Hence , the formula of the compound is M₂N₃.