Atoms of element B form hcp lattice and those of the element A occupy 2/3rd of tetrahedral voids. What is the formula of the compound formed by these elements A and B ?

Atoms of element B form hcp lattice and those of the element A occupy

1.	Atoms of element B form hcp lattice and those of the element A occupy 2/3rd of tetrahedral voids. What is the formula of the compound formed by these elements A and B ?
Answer» Solution :Suppose NUMBER of atoms B in hcp lattice =n As number of tetrahedral voids is double the number of atoms in the CLOSE packing , therefore, number of tetrahedral voids =2n As atoms A occupy 2/3rd of the tetrahedral voids, therefore, number of atoms A in the lattice =`2/3xx2n="4n"/3` `therefore` Ratio of A:B=`"4n"/3:n=4/3:1=4:3` HENCE, the FORMULA of the compound `A_4B_3`