By Doping Method. Doping methods involve the addition, to the original sample, of known amount(s) of the phase(s), the fraction of which is (are) to be determined. The corresponding equations, deduced with no approximation, relate the fraction of the phase to be determined to the intensities diffracted by that phase and by any non-added phase (reference phase) which is present in the sample, before and after doping. The intensity–fraction equations are free of the matrix effects—absorption coefficients.

Please be more precise in your question. What do you want to learn about the unknown phase?

Do you want to know if this is a previously unknown new crystal structure?

Do you want to know which material the phase is ?

Do you want to know the relative amount in your sample?

Thank you Prof. R. B. Neder for mentioning the possible queries.

My question is if I have a unknown phased material (which I have do not any JCPDS data) then how can we interpret from it's diffraction data about the phase, crystal structure, constituent materials?

for an unknown material, you should analysize the element composition by chemical analysis or ICP.

then, you can measure XRD spectra (slow scanning) and then calculate and simulate the crystal structure by software , Materials studio or Rietveld refinement. then you can get the detailed information about atom position and phase structure of the unknown materials.

Thank you Prof. Zhonghua Yao for the answer.

It is well we can proceed for the EDS like elemental composition analysis.

But I am taking about phase analysis only by XRD analysis.

But if I don't have the JCPDS file or CIF file corresponding to the unknown material then how can I proceed for the Rietveld refinement?

To determine the crystal structure of an unknown phase from powder diffraction data you need to read up on this topic in the abundant relevant literature with keywords like "crystal structure solution powder diffraction" Many text books exist, introductory chapters are in Dinnebier & Billinge "Powder Diffraction"; Google scholar will find you plenty of papers and reviews.

One typically has to:

1) index the pattern, i.e. find the correct unit cell parameters for the material

2) Integrate the Bragg reflections, overlapping relections need to be partitioned into th eindividual reflections

3) Run the crystal structure solution

4) Verify with a Rietveld refinement.

A program that will do this is "endeavour" by Crystal Impact

That's right, for an unknown materials usually we use compounds analysis first, for example using XRF (X-ray Flourcence).

After we know compound in the material we use XRD method for getting xrd spectrum. Comparing spectra with certain spectra (peaks) in the standard collection, we know the phase of measured material.

If you have a compound with a composition X_1 Y_2 Z_3, and if the standard XRD pattern is available, you can find it out by just picking up the peak positions. If the standard data is not available, you can find the structural details but not the elemental compositions.

Thank you prof. Dharmadoss Sornadurai for the answer.

Can you kindly elaborate how can I get composition and structural details of unknown if the standard XRD pattern is available?

I have mentioned clearly that even for an unknown phase (only if it is a single phase) you can find out the lattice parameters and space group. If some other compounds exist with similar structures and the same number of atoms in the unit cell you can try to invoke the atomic that well-established phase to the unknown (again I am repeating that the sample should be mono-phasic nature).

I have mentioned clearly that even for an unknown phase (only if it is a single phase) you can find out the lattice parameters and space group. If some other compounds exist with similar structures and the same number of atoms in the unit cell you can try to invoke the atomic that well-established phase to the unknown (again I am repeating that the sample should be mono-phasic nature).

Thank you Prof. Dharmadoss Sornadurai for the answer.

High-quality XRD data is necessary for determining the crystal structure of the unknown phase. The possible space group and corresponding lattice parameters could be obtained after pattern indexing. And then the structure could be solved by direct method, direct space method, etc.

Thank you Dr. Menghu Zhou for the answer.

You can determine the phase of an unknown compound by XRD data.

After the data collection you need to analyze the obtained diffraction pattern. The diffraction pattern will consist of a series of peaks that corresponds to the crystal planes within the sample. From the position and intensity of these peaks, one get to know about the crystal structure and phase of the compound. Compare the obtained diffraction pattern with existing database of known crystal structures. By matching the positions and intensities of the diffraction peaks you can identify the phase present in your sample.

Thank you Aayush Bhardwaj

The effectiveness of phase identification by XRD is dependent on the diffraction pattern's quality, the presence of distinct and well-separated peaks, and the accessibility of a thorough and precise database for comparison.

Dear Dr. Aruna, a question about the unknown compound. For unknown compounds which database you will choose comparison? Please try to understand if you want to characterize the unknown compound or new materials there are other trial-and-error methods available. The first step is to try to find out the composition and phase purity, the second step is to record the XRD pattern and identify all the peaks (need not be well separated), from these XRD peaks one can get the lattice parameters and space group. Then look for similar stoichiometric materials and try to find out the atomic positions using the Rietveld method.

Thank you sir

Thank you Mr. Wajid Ali for your answer.

The compound is unknown means how will you give the input elements for the Match software and the ICDD data search? So, first do the EDAX and try to find out the composition of the phase then you can find out the structure from the ICDD Data.

The compound is unknown means how will you give the input elements for the Match software and the ICDD data search? So, Sougata Koner first do the EDAX and try to find out the composition of the phase then you can find out the structure from the ICDD Data.

The compound is unknown means how will you give the input elements for the Match software and the ICDD data search? So, Sougata Koner first do the EDAX and try to find out the composition of the phase then you can find out the structure from the ICDD Data. @

To identify a particular phase both peak positions and relative intensities must fit.The d-spacing of each peak is then obtained by solution of the Bragg equation for the appropriate value of λ. Once all d-spacings have been determined, automated match routines compare the ds of the unknown to those of known materials. A systematic procedure is used by ordering the d-spacings in terms of their intensity beginning with the most intense peak.

Thank you Dr. Nabiha Abdo for the answer.