Fig. 4. Fits to the (a) MnWO₄ and (b) FeWO₄ product phases, using wolframite-MWO₄ structures from the ICSD (code 67 906 (ref. 42) and 26 843,⁴³ respectively). Details of the fits are found in tables of Fig. S6 in the ESI.† (c) Results from reverse sequential real space Rietveld refinements of MnWO₄ and FeWO₄ structures to the PDFs in the range of 1.3–60 Å. Scale factor, crystallite size (cr. size) in nm and isotropic ADPs (u_iso in Ų) for W and Mn/Fe are shown in addition to ΔW_y, which is the atomic position deviation of W from the octahedral center (defined as 0.13), along the y-axis. The time range where the FeWO₄ intermediate phase is present is highlighted with a grey colour.