Chemistry - Solid State Question with Solution | TestHub

In a cubic close-packed (ccp) lattice, let the number of atoms forming the lattice be $N$.

The number of octahedral voids generated in a ccp lattice is equal to the number of atoms forming the lattice, which is $N$.

Since atoms of element Y form the ccp lattice, the number of Y atoms is $N$.

Since atoms of element X occupy all the octahedral voids, the number of X atoms is also $N$.

The ratio of the number of atoms of X to that of Y is $N:N=1:1$.

Therefore, the formula of the compound is $\text{XY}$.

Answer: $\text{XY}$