Oxidative Precipitation as a Versatile Method to Obtain Ferromagnetic Fe ₃ O ₄ Nano‐ and Mesocrystals Adjustable in Morphology and Magnetic Properties

Oxidative precipitation is a facile synthesis method to obtain ferromagnetic iron oxide nanoparticles from ferrous salts—with unexplored potential. The concentration of base and oxidant alone strongly affects the particle's structure thus their magnetic properties despite same material, magnetite (Fe3O4), obtained when precipitated with potassium hydroxide (KOH) sulfate (FeSO4) treated nitrate (KNO3) at appropriate temperature. Depending on concentrations, it possible series different types either single crystals or mesocrystals. time-dependent mesocrystal evolution can be revealed via electron microscopy provides insights into process oriented attachment, yielding faceted particles, showing facet-dependent reactivity. It found that influences ligand exchange crystallization pathways. presence ions contributes as well, apparently hinders further crystal fusion, infrared spectroscopy. Finally, nitrite, one ecologically highly relevant reduction product occurring in nature context iron, only evolves if reaction quantitative.