Question

Third nearest neighbour distance in fcc

Answer 1

Explanation:

The nearest neighbors of any apex in FCC are the atoms in the middle of a face. And there are 8 such atoms, at a distance (a√2)/2=0.707a. The next neighbors are in the center of the cube, and there are 8 such atoms, at a distance (a√3)/2=0.866a. The third next neighbors are the 6 next apexes, with a distance a.