Atoms of element B form hcp lattice and those of the element A occupy `2//3^("rd")` of tetrahedral voids . What is the formula of the compound formed by the element A and B ?

Explanation

The number of tetrahedral voids formed is equal to twice the number of atoms of element B and only 2/3rd of these are occupied by the atoms of element A. Hence the ratio of the number of atoms of A and B is `2 xx (2//3):1 or 4:3` and the formula of the compound is `A_(4)B_(3)`.