If the radius of an anion is double that of a cation,the coordination number of the cation and the type of hole occupied are respectively:

If the edge length of a cubic unit cell in an $fcc$ structure is $620 \ pm$, then the atomic radius of the element will be ............... $pm$.

In a mineral $MX_2$,$M^{+2}$ ions are arranged in a $ccp$ structure and $X^{-}$ ions occupy the tetrahedral voids. What are the number of cations and anions per unit cell,the coordination number of the cation,and the percentage of occupied tetrahedral voids,respectively?

Which set of following characteristics for $ZnS$ crystal is correct?

In the fluorite structure,the coordination number of $Ca^{2+}$ ion is

Potassium crystallizes in a $bcc$ lattice,hence the coordination number of potassium in potassium metal is