The optical properties of nano-structural α-FeO dependence on the shape.

Three different crystal morphologies of α-FeO, including uniform hexagonal, square, and rhombic shapes, were prepared according to the aqueous-thermal reaction. The hexagonal-shaped α-FeO was enclosed by the 104 plane, while the square and rhombic structures were enclosed by the 110 plane. Two absorption peaks at 455 and 532 cm were found for the perpendicular (⊥) modes, and one absorption peak at 650 cm appeared for the parallel (||) mode for hexagon-shaped α-FeO during analysis by Fourier-transform infrared spectroscopy.