by six intense peaks i was reffering to (220,311,400,422,511,440) of spinel crystal structure and i want to know which peak gets affected by which cation or by which site they are related to.
In X-ray diffraction all peaks are affected by all details of the structure. In order to separate different contributions you have to take into account as many peaks as possible and perform the least squares analysis (the most popular approach nowadays is called Rietveld refinement).
Thanx for your reply Alexander, but i am concerned about the effect of cation distribution on peak in spinel structure and want to know which peak is related to which site or i must say which cation. If you could help me more on this topic, i would be highly privileged.
Once more. XRD is not like XPS or NMR, where it is possible to assign some atom or small group to each of the peaks. In XRD all sites contribute to all peaks. In some cases it is possible to find a simple relationship between intensities of a few wisely selected peaks and some interesting structural feature (like famous Dahn's intensity ratio for LiCoO2), but even these relationships will only work if you are absolutely sure that there are no other changes in the crystal structure or experimental conditions.