The structure of $MgO$ is similar to $NaCl$. What would be the coordination number of magnesium?

What is the coordination number of the $Ca^{2+}$ ion in the fluorite structure?

What is the coordination number of a particle in a simple cubic close-packed structure?

In a face centred cubic lattice,atom $A$ occupies the corner positions and atom $B$ occupies the face centre positions. If one atom of $B$ is missing from one of the face centred points,the formula of the compound is:

What is the coordination number of sodium in $Na_2O$?

For an ionic crystal $A^{+}B^{-}$ with coordination number $6$,the radius ratio will be