In a compound, atoms of element Y form hexagonal close-packed structure. Atoms of element X occupy 2/3 of the octahedral voids. What is the formula of the compound?

Step-by-step solution

Let the number of atoms of element Y forming the hexagonal close-packed (hcp) lattice be N . The number of octahedral voids in a close-packed structure is equal to the number of atoms forming the lattice, which is N . Since atoms of element X occupy 2 3 of the octahedral voids, the number of atoms of X is 2 3 N . The ratio of the number of atoms of X to that of Y is 2 3 N : N = 2 : 3 . Thus, the formula of the compound is X ₂ Y ₃ . Answer: X ₂ Y ₃