Potassium crystallizes in a $bcc$ lattice. What is the coordination number of potassium in the potassium metal?

What is the total number of particles present in a $bcc$ unit cell?

What is the coordination number of $Zn^{2+}$ and $S^{2-}$ ions in the zinc blende $(ZnS)$ structure?

For an ionic crystal of the general formula $AX$ and coordination number $6$,the value of radius ratio will be

The structure of $TlCl$ is similar to $CsCl$. What would be the radius ratio in $TlCl$?

$A$ cubic structure is formed where atoms of element $X$ are occupied at the corners of the cube and also at the face centers. Atoms of element $Y$ are present at the body center and at the edge centers. If all the atoms are removed along a plane passing through the middle of the cube (bisecting the four edges), the formula will become