Question

Synthesis of iron oxide nanoparticles by hydrothermal method

Answer 1

FeO is also not ferromagnetic, but it is pulled about twice as much as Fe2O3 towards the poles of a magnet. Magnetite, Fe3O4, is ferromagnetic, and is about 1/4 as strong as pure iron. One warning is that rust may be a collection of the different oxides quite possibly other contaminants.