Determine which x-ray reflections are systematically zero for reflections from a face centered cubic lattice.By finding a simplified expression for F^2 for the diamond structure determine which reflections are observed in this case.The diamond lattice is cubic and contains atoms at the following fractional coordinates: 000,0 1/2 1/2 ,1/2 0 1/2 ,1/2 1/2 0, 1/4 1/4 1/4, 1/4 3/4 3/4, 3/4 1/4 3/4,3/4 3/4 1/4