The coordination number of $Ba^{2+}$ ion in Barium fluoride $(BaF_2)$ is $8$. What must be the coordination number of fluoride ion $(F^{-})$?

How is the anti-fluorite structure derived from the fluorite structure?

In the face-centred cubic $(FCC)$ lattice structure of gold, the closest distance between gold atoms is ('a' being the edge length of the cubic unit cell).

$A$ compound formed by elements $X$ and $Y$ crystallises in a cubic structure, where $X$ atoms are at the corners of a cube and $Y$ atoms are at the body centre. The formula of the compound is:

If three elements $A, B, C$ crystallize in a cubic solid lattice with $B$ atoms at the cubic centers, $C$ atoms at the center of edges, and $A$ atoms at the corners, then the formula of the compound is

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