In a face centered cubic unit cell, the volume occupied by the particles of the substance is about 74% of the total unit cell. First, we find the volume of a single atom assuming it to be sphere: Volume(atom) = 4/3 x π x r³ Volume(atom) = 4/3 x π x (197 x 10⁻¹²)³ Volume(atom) = 2.87 x 10⁻²⁹ m³
There are a total of 4 atoms in a FCC unit cell, so the total volume occupied by atoms is: 2.87 x 10⁻²⁹ x 4 = 1.15 x 10⁻²⁸ m³
Volume of cell = (1.15 x 10⁻²⁸ ) / 0.74 Volume of cell = 1.55 x 10⁻²⁸ m³
