The two graph attached here show FTIR and XRD of material (ZnO) form the same paper. i can not make out why some the molecules like nitric acid group present in the ZnO as shown by FTIR does not show its presence in XRD graph?
Hi Zain Pirzada ,
The two techniques are very different, and it gives you different information. The FTIR gives you information about the chemical environment and the presence of organic and inorganic groups. It is an absorption phenomena that generates vibration of the groups in the material.
The XRD is a technique that measures X-ray intensity of diffracted light. Completely different setup. It gives you information about the crystal structure, not the presence of some organic groups on the surface or such things.
I advise you to read and review about the two techniques since appears that you don't have yet the theoretical background to have a good understanding.
Kind Regards,
GG.
Gustavo Henrique de Magalhães Gomes dear thank you for your response. i have already studied about FTIR and XRD. can you guide me to a good source so that i can understand these concepts more clearly?
as far as my question is concerned, the groups present in material as revealed by FTIR are not shown by XRD? Can't we consider these functional groups in the material of ZnO as impurity?
Zain Pirzada
You are confusing 2 different things as Gustavo Henrique de Magalhães Gomes states. It's analogous to saying aren't silver and gold the same because they're both elements? Or confusing a tractor with a car when the function of these 2 vehicles is totally different. If one chemical or physical technique solved all our problems why do you think that there'd be literally hundreds of them in existence?
Things to consider - look at the penetration depth of each technique; look at bulk versus surface composition; structural versus chemical composition, and so on.
Now XRD probably needs at least 1% of another phase to be detectable. In the case of wanting elemental analysis you may want to go to XRF (and will you say that they're the same because they both use x-rays?) or ICP.
We don't go to our car with a single tool - we have a suite of tools to fix the car. In the same way, in the laboratory, different techniques provide different information about our sample(s).
Ask your colleagues, professors, and library what text books they used. In my day, now being a curmudgeon, I used Klug and Alexander as my go to XRD book: X-Ray Diffraction Procedures: For Polycrystalline and Amorphous Materials H P Klug, L E Alexander John Wiley & Sons, New York, NY (1954) - you can get a copy on Abebooks for less than $10 including shipping within the US. We only had IR and UV-VIS in my day - computing wasn't at a stage to allow FTIR. So you can see how much has changed in a person's lifetime...
These are completely different methods, colleagues are right (I don’t think it needs any confirmation...). Roughly speaking, IR-FTIR gives an energy spectrum, often interpreted as evidence of different functional groupings (short-range order). Powder X-ray diffraction analysis provides information on the crystal structure of a substance, i.e. about long-range order there. For example, if you take a paraffin at room temperature, then the IR-FTIR spectrum will exist, but the X-ray diffraction analysis will give a picture of a completely amorphous substance (background only).
In my opinion, familiarity with the methods should start with "Solid State Chemistry and its Applications" by A.R. West. This book is easy to find on the Internet. But you need to start at the very beginning of this book, as I see it.
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