Rietveld refinement of a wrong crystal structure
Rietveld refinements are used to confirm crystal structures solved from powder diffraction data. The Rietveld refinement of the X-ray powder pattern of
γ-quinacridone with the crystal structure of
β-quinacridone gives a good fit, and a reasonable looking crystal structure. However, the lattice parameters, molecular conformation and packing are wrong. This example shows that a successful Rietveld refinement is not always final proof of the correctness of a crystal structure.
C. Buchsbaum and M.U. Schmidt