Dear all,
I am working with powder samples which are synthesized and some were purchased directly. In this regard, I use Gaussian 09 software to find optimized parameters like bond lengths and bond angles theoretically. I wish to now find the experimental bond lengths and angles for my compound. Since, they are powders I can record only powder xrd. How to obtain the bond length and angle parameters for those compounds. Whether it is possible from powder xrd data or any other experimental facility available.
As far as I know you cannot get structure information if you only get some knowledge about the crystal lattice. Of course, the intensity includes the atomic positions but since you have only a few reflections and perhaps many atoms the projection on one dimension is not sufficient. For your application you need the full crystal structure description. This is commonly done using single crystals and specific diffractometer measuring the intensity for an immense number of directions (2D).
One can do refinement also with powder, and obviously there are also new approaches which enable a structure solution also from powders, but with certain limitations. Distances you can probably also determine by some other exclusive techniques like IR spectroscopy etc.
Generally X-ray crystallography or NMR techniques are used for structure determination. For small molecules even mass spectrometry along with elemental analysis can do the trick for you.
One can get functional group information with IR spectroscopy but that alone will not be sufficient.
First we should know which material you are talking about. There are solutions for you problem if the crystal structure is of high symmetry (cubic would be certainly trivial) and/or the complexity of the motive is low. Rietveld solutions have been obtained for those cases and you may not need a single crystal.
If you know the structure of its compound (or there are any isostructural compound reported), then you can refine the XRD data with the Rietveld method and obtain the bond lengths and angles parameters (among other information).
Dear all,
Thanks for your kind information. I know the structure of my compound Fernando. Kindly let me know how to do the rietveld refinement. I will try it once now to obatain the parameters.
For the Rietveld refinements you can use, for example, the WinplotR program (which is within Fullprof pack (https://www.ill.eu/sites/fullprof/)). It is not trivial to use this program. You need create a .pcr file with the initial structural parameters of you compound and then, start to refine these parameters and obtain a theoretical DRX pattern that simulate the experimental one. With this, you can draw the refined crystallographic structure and obtain the bond distances and angles.
If you know the structure why don't you calculate all bonding length or angles between them? You don't need an XRD pattern. F. Pomiros answer is directed to a case where you don't know your structure but you perhaps have an educated guess and want refind the model to your experimental data.
The simple way to estimate bond lengths and bond angles is to use programs for visualization atoms ( molecules) like PowderCell for example. You need to know structure ( space group,atom positions and cell parameters).
If the structure is known, any molecule visualization software can be used.
There are many ways to skin a cat. You should tell us what information you have. All answers are a collection of " if you........." but we do not know what can we put in your dotted line. So display all your information, material, aggregation, instruments available, etc.
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