The coordination number in $hcp$ is

All of the following share the same crystal structure except:

If the distance between $Na^{+}$ and $Cl^{-}$ ions in sodium chloride crystal is $X \ pm$, the length of the edge of the unit cell is

The coordination number of a sphere in a face-centered cubic $(fcc)$ lattice is .....

$A$ compound is formed by elements $A$ and $B$. Element $A$ occupies the corners of the cube,and element $B$ occupies the face centers. What is the formula of the compound?

The ratio of the effective number of atoms in a unit cell of $fcc$ and $bcc$ lattices is