How many formula units are present in the unit cell of fluorite $(CaF_2)$?

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

If the cation is present in the tetrahedral void,what is the radius ratio ${r_ + }/{r_ - }$?

How many atoms are there in a cube-based unit cell,having one atom on each corner and $2$ atoms on each body diagonal of the cube?

What is the coordination number of a sphere in a simple cubic lattice?

$A$ compound of $A$ and $B$ crystallises in a cubic lattice in which $A$ atoms occupy the lattice points at the corners of the cube. The $B$ atoms occupy the centre of each face of the cube. The probable empirical formula of the compound is