In antifluorite structure,the negative ions

The compound forming $ccp$ structure contains $9.6 \times 10^{23}$ atoms. Find the number of tetrahedral voids formed in it.

The number of octahedral and tetrahedral holes respectively present in a hexagonal close packed $(hcp)$ crystal of $X$ atoms are

The molecular formula of a compound is $AB_2O_4$. Atoms of $O$ form a $ccp$ lattice. Atoms of $A$ (cation) occupy $\frac{1}{8}$ of the tetrahedral voids. Atoms of $B$ (cation) occupy a fraction of the octahedral voids. What is the fraction of vacant octahedral voids?

$A$ compound is formed by two elements $X$ and $Y$. The element $Y$ forms a cubic close-packed $(CCP)$ arrangement and the atoms of element $X$ occupy one-third of the tetrahedral voids. What is the formula of the compound?

The molecular formula of a crystal is $AB_2O_4$. Oxygen atoms form $ccp$ lattice. Atoms of $A$ occupy $x \%$ of tetrahedral voids and atoms of $B$ occupy $y \%$ of octahedral voids. $x$ and $y$ are respectively: