LAUSR

Abstract This paper addresses the disparity that exists among different estimations of the structural parameters obtained from an identical structure using the Rietveld refinement. Firstly, we inter-compare the previously reported lattice parameters by reconsidering several powder diffraction patterns belonging to hexagonal, orthorhombic and tetragonal Bravais lattice types. The inter-comparison establishes linearity among the estimated lattice parameters, indicating that the obtained unit-cells in the Rietveld refinement are proportional to each other. Secondly, we clarify that the disparity that occurs at the analysing stage cannot be explained by the systematic/random errors in the data or by the difference of the wavelengths between the experimental and the analytical ones used in the refinement programs. Thirdly, we show that evaluating the peak-shift is useful to judge the correctness of a Rietveld fit. Our study could help developing a methodology to minimize/remove the mismatch in the unit-cells obtained by different Rietveld refinements from the identical powder diffraction pattern.