Response to “Does BaTbO3 Adopt the P1 Symmetry?”: Response to “Does BaTbO3 Adopt the P1 Symmetry?”

Space group assignment for a Perovskite compound is a complex task when only powder X-ray diffraction data obtained with K-alpha (both K-alpha 1 and K-alpha 2) radiation is available. Whole profile refinement of powder X-ray diffraction data using Rietveld method is very good to check if the structural model is OK. However, it could not tell us that it is the only model to fit the data. More data are needed, such as X-ray diffraction data obtained with single wave radiation (from K-alpha 1 only or from synchrotron), neutron diffraction data, and/or electron diffraction data.