The packing efficiency and coordination number of face-centred cubic $(FCC)$ lattice is

What are the coordination numbers of $bcc$,$scc$,and $fcc$ respectively?

An ionic compound has unit cells consisting of $A$ ions at the corners of a cube and $B$ ions on the centres of the faces of the cube. The empirical formula of this compound is

The coordination number of an atom in a body-centered cubic $(BCC)$ structure is:
[Assume that the lattice is made up of atoms.]

What is the coordination number of $Cs^{+}$ and $Cl^{-}$ ions in the $CsCl$ structure?

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?