In the diffractogram given in Figure 2 for an unknown material, the following procedure is adhered:

Steps :

1. Firstly, the 2θ values where diffraction occurred are obtained,
   
2. Subsequently, the corresponding θ, sin θ and sin²θ values for all the peaks are noted,
   
3. The ratios of sin²θ value of all the peaks with respect to the first peak is obtained,
   
4. Finally, the obtained ratios are multiplied by a suitable integer to convert all these ratios into an integer.
   
   

5. The distinction between lattices of the cubic system is possible by using the fact that not all combinations of h²+k²+l² lead to reflection for a given lattice. The ratio of h²+k²+l² values for allowed reflections from different crystals are as follows [3]:
   
   

It is clear from the above table that the unknown material whose diffractogram is given is an FCC material.