• For a face centered cubic (fcc) unit cell , the radius r and edge length/lattice constant (a) is given by :
4r = √2 a ; given that radius = 164pm
∴ 4 * 164pm =√2 a
∴ a = (4*164pm) /√2
= 463.86 pm
≈464 pm
• The lattice constant (a) of a crystal M = 464pm