The vacant space in $bcc$ lattice unit cell is ............ $\%$

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

Calculate the volume of $fcc$ unit cell in $cm^3$ if void volume of it is $4.16 \times 10^{-24} \ cm^3$.

What are the percentages of empty space in a cubic close-packed $(CCP)$ structure and a body-centered cubic $(BCC)$ structure,respectively?

$A$ solid has an $hcp$ lattice. Atoms of $Z$ (anions) form the $hcp$ lattice. Atoms of $X$ (cations) occupy all the octahedral voids in the lattice. Atoms of $Y$ (cations) occupy half of the tetrahedral voids. What is the molecular formula of the solid?

Find the void volume of a $bcc$ unit cell in $cm^3$ if the volume of the unit cell is $1.5 \times 10^{-22} \ cm^3$.