What is cubic close packed structure?

Cubic close packed (CCP) structure, also known as face-centered cubic (FCC), is a type of crystal lattice arrangement where spheres are packed together in the most efficient way, achieving a maximum packing density of approximately 74%. In this structure, each unit cell contains four atoms, with one atom located at each corner of the cube and one at the center of each face. The atoms in a CCP structure are arranged in layers, with each layer alternating in position to maximize space utilization. Common examples of materials with a CCP structure include metals like aluminum, copper, and gold.