Partial FeO–Fe3O4 Phase Transition Along the <111> Direction of the Cubic Crystalline Structure in Iron Oxide Nanocrystals

Abstract The iron oxide nanocrystals described herein stem from a ketonic decarboxylation reaction which fosters the delivery of –FeO– as an intermedium product. This intermedium product working as a monomer nucleates into FeO seeds which grow to attain a cubic shape with tips. This kinetically‐controlled second stage of growth favors the deposition of –FeO– at the apexes and promotes a partial topochemical FeO to Fe 3 O 4 phase transition mainly along the elongated <111> direction of the cubic crystalline structure.