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Rietveld School

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Spot the Errors

Learning Outcomes: How to trouble shoot a Rietveld refinement.

Your supervisor has recorded some diffraction data on a crystalline sample of what he believes to be Y2O3 and asks you to refine the structure from the data. Apart from file mistake_01.xy each data set provided contains a fundamental error. Can you find the errors?

A target Rwp value (using a TCHZ peak shape) is given in each case for isotropic temperature factors. A small prize to the first person who cracks all 8!

The following files might be useful: y2o3_maslen.cif; ho2o3_152458.cif; sm2zr2o7_150208.cif

Experimental Data Files

mistake_01.xy - target 14.3%

mistake_02.xy - target 18.9%

mistake_03.xy - target 12.4%

mistake_04.xye -target 14.6%

mistake_05.xy - target 13.2%

mistake_06.xy - target 14.4%

mistake_07.xy - target 12.0%

mistake_08.xy - target 15.3%

 


Modified 03-Apr-2014 by John S.O. Evans.