I did XRD on anhydrous sodium sulfate salt (purity>99%) which i bought couple of months ago. For some reason sodium sulpfate peaks from PDF database (anhydrous or hydrated) don't align with the peaks of my xrd data. Could someone please have a look what could be the possible reason? I have attached the .raw file and the product chemical certificate.
You'll find attached a report with your XRD pattern. It is indeed thenardite (anhydrous sodium sulfate), but your peaks are shifted towards higher 2 theta. It could be because your diffractometer is not well aligned. You should run NIST standard and check if everything is fine with your equipment. Also, your sample has texture (preferred orientation) effects and this is why the PDF file intensity does not match quite well with the observed one.
I hope this helps.
You'll find attached a report with your XRD pattern. It is indeed thenardite (anhydrous sodium sulfate), but your peaks are shifted towards higher 2 theta. It could be because your diffractometer is not well aligned. You should run NIST standard and check if everything is fine with your equipment. Also, your sample has texture (preferred orientation) effects and this is why the PDF file intensity does not match quite well with the observed one.
I hope this helps.
Thanks a lot Martin for your detailed explanation,
I'll check with my lab technical officer for possible alignment issues.
The particle size (as received) was coarse as well, i'll try to redo xrd by grinding it to finer particle size.
After checking your diffractometer, if you get the same results try drying your sample before the test.
Dear Martin,
Could you please provide me the method by which you managed to identify there is a peak shift. I shifted the whole scan through "x factor" shift in Brukers Diffrac Eva software and it aligned perfectly.
Dear Rajeev,
I didn't do anything special. I just compared your peak positions with the peak positions listed in the PDF file 00-037-1465. Although the peak shifts can also be attributed to different unit cell parameters usually they are not as severe and persistent through the whole pattern as in your sample.
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