Silver adopts a face center cubic unit cell structure illustrate how the number of atoms per unit cell for that silver atom are obtained. All right, so remember we have eight corners to our queue, so each one is 1/8 of an atom, and we have eight corners involved, so 18 × 8 = 1 atom.
Also remember that on each face we have half of a sphere, and there are six faces faces to a cube, so that's times 6. So that's going to give us 3 atoms when we add them together. That explains why a face center cubic unit saw is 4 atoms per one unit cell.
So this is our atoms 2 unit cell ratio. It's a four to one ratio.
