In an $AgI$ crystal,$I^{-}$ ions form a close-packed structure. What percentage of the tetrahedral voids is occupied by $Ag^{+}$ ions?

An element crystallizes in a structure such that the unit cell is a cube with one atom at each corner and two atoms on its body diagonal. If the volume of this unit cell is $24 \times 10^{-24} \, cm^3$ and the density of the element is $7.2 \, g \, cm^{-3}$,calculate the number of atoms present in $200 \, g$ of the element.

The number of octahedral sites per sphere in a $fcc$ structure is

$A$ solid has a structure in which $W$ atoms are located at the corners of a cubic lattice, oxygen atoms at the edge centres, and $Na$ atoms at the body centre. The formula of the compound is:

What is the minimum limiting radius ratio for an octahedral arrangement?

Explain the calculation of the number of atoms in a body-centered cubic $(bcc)$ unit cell.