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 ............... $pm$.

The arrangement of $X^{-}$ ions around $A^{+}$ ion in solid $AX$ is given in the figure. If the radius of $X^{-}$ is $250 \ pm$, the radius of $A^{+}$ is: (in $pm$)

In a face-centered cubic $(FCC)$ lattice,$A$ atoms are present at the corners and $B$ atoms are present at the face centers. If one $B$ atom is removed from one of the face centers,what will be the molecular formula of the compound?

The coordination number of the point $B$ for a solid with the following structure is:

Which one possesses an antifluorite structure?

What is the minimum value of the radius ratio ${r_ + }/{r_ - }$ for $NaCl$ to ensure that anion-anion contact does not occur?