Question

Atoms of element b from hcp lattice and those of element a occupy two third of tetrahedral void what is the formula of the compound formed by element a and b

Answer 1

Number of atoms in hcp lattice is 6.
B occupying hcp lattice means no of atoms of B are 6.
No. of tetrahedral voids are twice no of atoms.
A is occupying two third of tetrahedral voids,
A =(2/3)*2*6 =8

A:B = 8:6 = 4:3

The formula of the compound is A4B3

Answer 2

$\huge\boxed{\underline{\mathcal{\red{A}\green{N}\pink{S}\orange{W}\blue{E}\purple{R}}}}$

• ❤.. The number of tetralhedral 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 ${2×(2/3):1 or 4:3}$ and the formula of the compound is ${A4B3}$.