The percentage of vacant space for $bcc$ unit cell is ............. $\%$

In an ionic solid, anions $(B)$ are arranged in an $hcp$ array and cations $(A)$ occupy $1/2$ of the tetrahedral voids. What is the formula of the ionic compound?

The number of tetrahedral voids per unit $HCP$ cell is

The ratio of densities if the same element undergoes $FCC$ and $HCP$ close packing is:

What is the type of hole occupied if the limiting value of $\frac{r+}{r-}$ is in the range of $0.225$ to $0.414$?

Potassium hexachloroplatinate $(K_2PtCl_6)$ adopts an antifluorite crystal structure. The corners and face centers of the cubic unit cell are occupied by :-