A Mossbauer study of FeSb[sub 2]O[sub 4]
^(121)Sb and ^(57)Fe Mossbauer effect measurements have been performed on FeSb[sub 2]O[sub 4], through the temperature range from 4.7°K to room temperature. Large quadrupole splittings are observed at both Sb site and Fe site, at 77°K and above. At 14°K, however, a local magnetic field also exists at Fe site. These confirm the results of previous studies that FeSb[sub 2]O[sub 4] is ferroelectric at room temperature and goes through a ferroelectric-antiferromagnetic phase at transition temperature T[sub c] = 46°K. Though a considerable magnetic field is present at the Fe site at temperatures below 46°K, the ^(121)Sb Mossbauer spectrum at 4.7°K shows no sign of magnetic splitting, indicating the absence of a magnetic field at the Sb site. The analysis suggests a Fe^(2+) magnetic configuration of A[sub x]G[sub y]C[sub z], which introduces a net magnetic field along c axis within each Fe chain and antiparallel magnetic fields between two adjacent chains. Due to the symmetric distribution of the surrounding Fe magnetic moments, the Sb ions experience almost zero magnetic field. The quadrupole doublets, at 77°K and above, are asymmetric. This arises from the anisotropic one-dimensional chain structure of Fe2+ in FeSb[sub 2]O[sub 4].