Structures and morphologies of goethite and its two synthesized Bloaded oxides,Ad-B-Goethite and Oe-B-Goethite,were characterized with the aid of IR,XRD and TEM,and their specific surface areas and Mn²⁺-adsorption capacities were measured with the BET method.It was found from IR that as compared with goethite,the two Bloaded geothites decreased in the bands of Fe-OH-Fe inplane bending at 888 cm^-1,the bands of Fe-OH inplane bending at 1 000 cm^-1,and the bands of free OH at 3100 cm^-1.The bands of bending modes of trigonal and tetrahedral boron were found at 458.5 cm^-1 with Ad-B-Goethite,and also at 527.2 cm^-1 and 476.5 cm^-1 with Oe-B-Goethite.XRD analysis showed that Ad-B-Goethite was still fine-FeOOH and Oe-B-Goethite was differed from goethite,suggesting that Oe-B-Goethite is probably a new mineral.Judging from TEM graphs,the particle of Oe-B-Goethite was smaller than that of goethite.The specific surface area of goethite,Ad-B-Goethite and Oe-B-Goethite was 108.4 m²g^-1,88.69 m²g^-1,and 120.5 m²g^-1,respectively.The increase in surface area means Oe-B-Goethite having more activity than normal goethite.This assumption is supported by the finding that the adsorption of Mn²⁺ on the surface of Oe-B-Goethite was the highest and that of goethite was the lowest in the three kinds of minerals.It was found that B in Oe-B-Goethite had replaced hydroxide ligands inside the crystal lattices,and inhibited crystal growth of goethite,thus resulting in weak crystallizability.It was also found that Mn²⁺ adsorption increased with the presence of Ad-B-Goethite,especially of Oe-B-Goethite.It is suggested that boron applied into soil functions is not only as a nutrient for plant,but also as a buffer against Mn²⁺ toxicity to the plant in the soil by forming B-loaded iron oxides.