Hello! Greetings to you too.

Well, a XRD diffraction pattern is like a "photography" of a material's unit cell. So, a phase is a pattern of one material, without

impurities. Once you have 3 phases, you will obtain a mixture of 3 different patterns, but represented like one.

You said you got a BCC, BCO and HCP, but in order to completely analyze your material, I need to know what you wanted to synthesize, so we can make a Rietveld Refinement.

I will also explain about crystallite size and lattice parameters.

Best regards,

Ricardo Tadeu

Ricardo Tadeu Maia .. I want to synthesize a photocatalyst..

but I didn't understand why u suggest doing Rietveld Refinement??

With a Rietveld Refinement, we can determine crystallite sizes and determine the lattice parameters of the 3 phases

Ricardo Tadeu Maia will you show me an example if u don't mind.?

This is an example of a Metal Organic Framework called ZIF-8. You can see the data obtained in the figure ZIF-8. Then, I can calculate a pattern from a known phase in order to compare what I have with the structure deposited in a crystallographic database, Figure 2. Softwares like VESTA and Mercury can do this, and the softwares o refinement do it too, like GSAS-II. I am using a structure from CCDC database, number 864310.

Initially, you can see that my data is not perfectly matched with the pattern from the database. So I can modify the lattice parameters of the model calculated, and then it match with the my data, and then I can determine what my parameters are.

About crystallite size, one of the methods to find it is the Scherrer Equation:

B = K . λ / (L . cos θ),

where B is the broadening, L is the crystallite size.

So, the crystallite size is inversely proportional to the peaks’ broadening, and you can adjust this with the refinement. There are instrumental influence in the broadening of peaks also, but the principal is the crystallite size.

Resuming, from this cubic structure initially with a=b=c= 16.9122 (Figure 2), and I modified to a=b=c= 17.0831 approximately to match my data (Figure 3). Adjusting the crystallite size to 250 nm approximately, and considering the instrumental parameters, it is possible to correct the broadening (Figure 4).

Basically, we need to do this process to your 3 phases.