The Diamond Structure

The diamond cubic structure is a distinctive of materials that have its constituent materials  bound in tetrahedral bonds. Insulators like carbon, semiconductors like Germanium, Silicon etc exhibit this crystal structure. The diamond structure is an FCC with a two atom basis. If one atom of the basis is at the FCC lattice point, say (0,0,0) the other atom of the basis is at (¼ a, ¼ a, ¼ a ) where a is the lattice constant of the FCC lattice. Thus the diamond structure can be arrived at by attaching one atom to each FCC lattice point  (x,y,z) and the other at a point ( (x+a/4), (y+1/4), (z+a/4) ).