What is the total volume occupied by atoms in a face-centered cubic $(FCC)$ unit cell of a metal?

In the fluorite structure,the coordination number of the $Ca^{2+}$ ion is.....

In a mineral $MX_2$,$M^{+2}$ ions are arranged in a $ccp$ structure and $X^{-}$ ions occupy the tetrahedral voids. What are the number of cations and anions per unit cell,the coordination number of the cation,and the percentage of occupied tetrahedral voids,respectively?

Which of the following has a $4:2$ coordination number structure?

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

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