Question

In a compound, atoms of element Y form ccp lattice and those of element X occupy $2/3^{rd}$ of tetrahedral voids. The formula of the compound will be

• A. $X_4Y_3$
• B. $X_2Y_3$
• C. $X_2Y$
• D. $X_3Y_4$

Answer 1

Answer: (A)

$X_4Y_3$

Answer 2

From the given data, we have
Number of Y atoms in a unit cell = 4
Number of X atoms in a unit cell
$= 8\times \frac{2}{3} = \frac{16}{3}$
From the above we get the formula of the compound as $X_{16/3}Y_{4}$ or $X_{4}Y_{3}$