$A$ solid $A^{+}B^{-}$ has a $NaCl$ type close-packed structure. If the radius of the anion is $250 \ pm$, what should be the ideal radius of the cation in $pm$?

$A$ compound made of elements $A$ and $B$ forms an $fcc$ structure. Atoms of $A$ are at the corners and atoms of $B$ are present at the centres of the faces of the cube. What is the formula of the compound?

What is the number of atoms present in the unit cells of a simple cubic,body-centered cubic,and face-centered cubic lattice of a monoatomic substance,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

In an $fcc$ structure,the location of the octahedral void is at ........

The crystal structure of the solid compound $XY$ is similar to $NaCl$. If the radius of the cation $X^+$ is $100 \, pm$, then the radius of the anion $Y^-$ will be ......... $pm$.