Fig. 6. (a) PDFs of the precursors forming on mixing each of the metal chloride precursors with Na₂WO₄ in water, compared to that of the individual precursors in water. The PDFs of the Zn–W and Fe–W sandwich-type clusters^8,20 described by Bøjesen et al.¹² and Barats et al.²² are plotted for comparison. (b) The ten best suggestions for describing the FeWO₄ precursor mixture, found by sifting through databases. Pearson correlation fitting was performed between calculated PDFs of all relevant clusters extracted from structures in the COD + ICSD databases and the obtained PDF in the range of 1–5 Å. Correlation coefficients are placed to the left of each structure. The structure visualizations were performed with VESTA.²⁴.