A M?ssbauer effect study of Fe3+ bearing γ-Fe2SiO4

Three synthetic Fe³⁺ bearing λ-Fe₂SiO₄ were analyzed using electron probe method, and the M?ssbauer spectra of the samples at 298 K, 150 K, and 95 K were measured. Each spectrum at three temperatures is composed of two doublets. These two doublets are assigned to Fe²⁺ in the octahedral sites and Fe³⁺ in the tetrahedral sites, respectively. Site occupancies were determined. The results show that Fe³⁺ and a small amount of Si⁴⁺ are in the tetrahedral and octahedral sites, respectively. The average bond lengths of the octahedral and tetrahedral sites were calculated according to the equations primarily given by Hill et al., O’Neill and Navrotsky and modified by the authors. Furthermore, the octahedral and tetrahedral bond lengths were used to calculate cell parameters and oxygen parameters. In addition, Fe³⁺ line broadening in the M?ssbauer spectra of Fe³⁺ bearing λ-Fe₂SiO₄ were interpreted by using the next nearest neighbor effects