In a hexagonal close-packed $(HCP)$ structure,the third layer covers the ........ holes created between the first and second layers.

In a $ccp$ structure of $X$ atoms,$Y$ atoms occupy the octahedral voids. If two $X$ atoms at the corners are replaced by $Z$ atoms,the molecular formula of the solid will be:

The structure of a mixed oxide is cubic close packed $(ccp)$. The cubic unit cell of the mixed oxide is composed of oxide ions. One-fourth of the tetrahedral voids are occupied by divalent metal $A$ and the octahedral voids are occupied by a monovalent metal $B$. The formula of the oxide is:

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?

Percentages of free space in cubic close packed structure and in body centered packed structure are respectively

In an ionic solid,anions $(B)$ are arranged in a $ccp$ array and cations $(A)$ occupy $1/3$ of the tetrahedral voids. What is the formula of the ionic compound?