Fig. 7. Magnetite formation from a white rust precursor phase by partial oxidation. (a–d) Cryo-TEM images and corresponding SAED patterns of (a) the product after addition of Fe2+ to the base solution, showing the formation of the Fe(OH)2 precursor phase, (b) the product 1 h after the addition of nitrate, showing additional reflections (indicated) but no morphological changes, (c) the product 2 h after the addition of nitrate, showing partial conversion to magnetite crystals, and (d) the product 24 h after the addition of nitrate, showing diffraction rings typical for magnetite. Reproduced from ref. 102.
