The number of tetrahedral voids per atom in a crystal is ......

$A$ compound forms a hexagonal close-packed $(HCP)$ structure. How many octahedral voids are present in $0.3 \, mol$ of it?

In a crystal lattice,anions $A$ form an $hcp$ array,and $2/3$ of the tetrahedral voids are occupied by cations $C$. What is the formula of the crystal?

What is the total number of spheres that surround the tetrahedral hole in a close-packed three-dimensional structure?

What type of crystal structure from the following has $52.36 \%$ packing efficiency?

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?