Find the void volume of $fcc$ unit cell in $cm^3$ if the volume of $fcc$ unit cell is $1.25 \times 10^{-22} \ cm^3$.

The packing efficiency of the two-dimensional square unit cell shown below is (in $\%$)

In a $ccp$ arrangement,what is the number of octahedral voids per atom?

How many unit cells share a corner of a unit cell in a crystal lattice?

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:

What is the total volume occupied by atoms in a $bcc$ unit cell (in $\%$)?