What is the percentage of void space in $bcc$ type of unit cell (in $\%$)?

If the radius ratio is in the range of $0.414 - 0.732,$ then the coordination number will be

The coordination number of $Ba^{2+}$ ion in Barium fluoride $(BaF_2)$ is $8$. What must be the coordination number of fluoride ion $(F^{-})$?

$A$ cubic lattice has $A$ atoms at the body centre,$B$ atoms at the corners,and $C$ atoms at half of the face centres. The formula of the lattice is:

The edge length of a face-centered cubic unit cell of an ionic substance is $508 \ pm$. If the radius of the cation is $110 \ pm$, what is the radius of the anion in $pm$?

The $FCC$ unit cell of a compound contains ions of $A$ at the corners and ions of $B$ at the centre of each face. What is the formula of the compound?