Abstract: Acicular α-Fe₂O₃ particles hydrothermally synthesized at 180℃ from Fe(OH) ₃ gel in the presence of morphological modifiers are characterized by transmission electron microscopy, X-ray diffraction, infrared spectroscopy and thermal gravimetric analysis. The influence of 4 modifiers on the formation of acicular α-Fe₂O₃ is compared by aging reaction at 100℃. The presence of HEDP and DMPG results in acicular and spindle crystals elongated along the c axis, tartaric acid and citric acid gave rod-like and short-column crystals. The choice of optimum reaction temperature depends on the modifier and its concentration.

Key words: hydrothermal reaction, α-Fe₂O₃, Fe₂(OH) ₃, acicular particle