(1) \(FeSO_4+BaCl_2\xrightarrow[]{}BaSO_4\downarrow+FeCl_2\)
(2) \(FeCl_2+2LiOH\xrightarrow[]{}Fe\left(OH\right)_2\downarrow+2LiCl\)
(3) \(Fe\left(OH\right)_2\xrightarrow[\text{chân không}]{t^{\circ}}FeO+H_2O\uparrow\)
(4) \(3FeO+2Al\xrightarrow[]{t^\circ}Al_2O_3+3Fe\)