I'm trying to refine by Rietveld Method a Al2O3-AlNbO4-NaNbO3 system, and I'm having some problems with a reflection on 44-45 2theta. I've used all CIF files of AlNbO4 that I could find, but I'm still not refining this reflection (or maybe more than one reflection) properly.
Can anybody tell me what is wrong? Or give me a hint to get a perfect refinement of this reflection?
By the way, using Popa Rules could not help me neither.
Thank you very much.