The Solid State

The correct answer is option (A): fcc>bcc>simple cube
The packing efficiency is the total space that is occupied by the atoms or ions, in a crystal lattice. FCC: The packing efficiency is 74%. The atoms are arranged in a cubic lattice and an atom is also placed at the center of each cube face. BCC: The packing efficiency is 68%. In this apart from the center an atom is located at each corner of the cube. Simple cubic: packing efficiency is 52%. The atoms are present in the cubic lattice and one atom is at each corner of the cube. So, the correct order will be: fcc>bcc>simple cube