Synthesis of Microcrystalline Hematite and Magnetite in Organic Solvents and Effect of a Small Amount of Water in the Solvents

Microcrystalline magnetite (Fe 3 O 4 ) particles having diameters of 7‐34 nm were synthesized by thermal treatment of iron(III) acetylacetonate in organic solvents at high temperatures (423‐573 K) and under autogenous pressures of the solvents. When the treatment was conducted in 1‐propanol containing a small amount of water (1‐3 vol%), nanosized hematite (α‐Fe 2 O 3 ) crystallized, which then was reduced to magnetite after a prolonged reaction time, indicating that a small amount of water in 1‐propanol drastically changed the reaction mechanism for the formation of iron oxides.