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 t...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展开更多
We studied four tourmalines with different Fe contents from Xinjiang,Sichuan,and Yunnan provinces of China using Mossbauer spectroscopy and single crystal X-ray diffraction.The valence and location of Fe in the four t...We studied four tourmalines with different Fe contents from Xinjiang,Sichuan,and Yunnan provinces of China using Mossbauer spectroscopy and single crystal X-ray diffraction.The valence and location of Fe in the four tourmalines and two heat-treated tourmalines have been investigated.The experimental results showed that Fe in the four tourmalines at room temperature had two valence states and two locations,i.e.Fe2＋（Y）,Fe2＋（Z）,Fe3＋（Y）.After being heated at 850℃ for 48 and 72 h,Fe elements in tourmaline were nearly completely oxidized and mainly occupied Y sites,and a small amount of Fe3＋ shifted to Z sites.Simultaneously,the amount of mixed valence state Fe 2.5＋ progressively increased with heating time,and electron delocalization occurred between the adjacent sites [Fe2＋-Fe3＋].展开更多
基金the National Natural Science Foundation of China(Grant No.40072019)the Japan Society for the Promotion of Science(JSPA)
文摘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
基金supported by National Natural Science Foundation of China(Grant No. 40672031)
文摘We studied four tourmalines with different Fe contents from Xinjiang,Sichuan,and Yunnan provinces of China using Mossbauer spectroscopy and single crystal X-ray diffraction.The valence and location of Fe in the four tourmalines and two heat-treated tourmalines have been investigated.The experimental results showed that Fe in the four tourmalines at room temperature had two valence states and two locations,i.e.Fe2＋（Y）,Fe2＋（Z）,Fe3＋（Y）.After being heated at 850℃ for 48 and 72 h,Fe elements in tourmaline were nearly completely oxidized and mainly occupied Y sites,and a small amount of Fe3＋ shifted to Z sites.Simultaneously,the amount of mixed valence state Fe 2.5＋ progressively increased with heating time,and electron delocalization occurred between the adjacent sites [Fe2＋-Fe3＋].
