In zinc blende structure,the coordination number of $Zn^{2+}$ ion is

Calculate the coordination number of $Na^{+}$ in $NaCl$ crystal, given the radii of $Na^{+}$ and $Cl^{-}$ are $95 \ pm$ and $181 \ pm$ respectively.

The ratio of anion radius to cation radius of a crystal is $10 : 9.3$. Then, the coordination number of the cation in the crystal is

$A$ unit cell of calcium fluoride has four calcium ions. The number of fluoride ions in the unit cell is

Potassium crystallizes with a

What is the value of the radius ratio for an ionic crystal having a coordination number of $6$?