Dear all, Thank you for the kind and helpful answers I received. They are much appreciated.
I have another issue with regard to some intensity mismatches i get in a powder x-ray pattern. I solved the structure of a compound by single crystal x-ray diffraction. I synthesized the same compound and the analog (just changing Co by Rh) in powder form to test the single crystal data and i obtained a low Rwp factor(3.4 %)for the Co compound. However, for the Rh compound a great deal of fluorescence was observed in the x-ray pattern (high background) and in spite of the fact that the single-crystal model fitted well ( Rwp 2.2 %)it is considered not suitable for publication. Recently, Our group has acquired a brand new x-ray powder diffractometer and the same Rh sample was used. The Rwp i get with the new data is 8.9%. A close look to the pattern reveals some overestimated peaks as well as underestimated peaks. The are no unfitted reflections and the peak positions are ok. It is a compound that crystallizes in the orthorhombic crystal system. Apparently there is not a clear pattern in the hkl values of these peaks that would indicate a preferred orientation problem. might it be an instrumental problem?. Any suggestion will be much appreciated regards -- Heriot-Watt University is a Scottish charity registered under charity number SC000278.
