From the XRD patterns, the diffraction peaks are related to single component (element) or compound say ZnO? for example, for ZnO film, peak may be due to Zn or O or ZnO, ZnO film grows along different orientations like (100), (200) etc, the peak intensity gives the amount of that particular phase, in ZnO film one can estimate how much amount of one phase relative to the other, but it is impossible to point out that in single phase (say ZnO (100), how much Zn or O is present from the XRD patterns. 

Hi Philipp,

From my understanding, I believe the intensities show how many counts of electron beams of certain direction of crystal structure of the materials, which are related with the orientation of the material itself. Furthermore, width shows how wide or narrow certain peak is, the narrower it is, the higher is the intensity of that certain direction of the crystal. Both the intensity and angle will determine the molar ratio, rather than a separate parameter individually.

However, peak intensity ratio couldn't be approximated from peak intensity ratio, especially with more complicated compounds (more than 2 distinct atoms). The best way is always to compare it with the database and get the closest match. From my experience, since my compound has 5 different types of atoms, hence sometimes either non-stoichiometric or impurity products also occured.

Hey guys,

thanks for your comments and suggestions. And also for the literature material.

Cheers from Munich,

Philipp

There may be software options to do this, depending on what package you have with your diffractometer.  You cannot do the quantification by direct comparison of intensities, since the intensity of peaks may be strongly affected by by various factors, including crystallite orientation effects.  A search/match function in the software can let you search you pattern against literature patterns, select one and fit it to one component of your pattern.  You then repeat this to match other patterns until all the peaks in your pattern are fitted.  The software can then give you the relative ratio of components, I believe by integration of areas in the peaks (not certain on the method, though).

The best way is fool profile analysis (Rietveld refinement)

Q. "Do I have a chance to roughly quantify from the peak intensity ratio, the molar ratio of these two components in the sample?"

A. Potentially, if you could calibrate the diffractometer with "known standard" mixtures of Ir & IrO2 and ignore or avoid or quantify "preferred orientation", particle size/strain/shape effects on the diffractograms :-)

Yes, the method is known with RIR acronysm ( Relative Intensity Ratio)

Any references  Marcella? Thanks!

Powder Diffraction: Theory and Practice, Robert E. Dinnebier

The Rir method is certainly overpassed by Rietveld refinement, but is still used in some field such as mineralogy

How do they account for the effect of "preferred orientation" and variations of the "Relative Intensity Ratio" as a result of particle size/strain/shape etc.?

Hello, i think we do that by using molecule weight , that is my problem now , i try to solve it

If you could send me the XRD data I can try quantifying by Rietveld method.