The coordination number is basically known as the number of spheres that directly surround a single sphere in a given crystal.
In other words, the number of nearest neighbors of any constituent particle present inside the crystal lattice is called as its coordination number.
The coordination number of :
Copper usually forms FCC crystal lattice.
The coordination number in a face-centered cubic close packing structure is known to be
In this lattice structure, each sphere in a three-dimensional arrangement has been surrounded by 6 spheres in its own layer and three spheres each in the lower layer and upper layer.
Thus, the nearest neighbors i.e coordination number for the FCC lattice for any sphere will be