Question

In a solid, atom $M$ occupies $ccp$ lattice and $1/3^{rd}$ of tetrahedral voids are occupied by atom $N$. Find the formula of solid formed by $M$ and $N$.

• A. $M_3N_2$
• B. $M_2N_3$
• C. $M_4N_3$
• D. $M_3N_4$

Answer 1

Answer: (A)

$M_3N_2$

Answer 2

Suppose number of $M$ atoms $= n$ Then number of tetrahedral sites $= 2 n$ Number of $N$ atoms $=\frac{1}{3}(2 n )$ Ratio $M : N = n : \frac{2}{3} n =3: 2$, i.e., formula is $M _{3} N _{2}$