Acta Phys. -Chim. Sin. ›› 2012, Vol. 28 ›› Issue (05): 1021-1029.doi: 10.3866/PKU.WHXB201202271

• THERMODYNAMICS, KINETICS, AND STRUCTURAL CHEMISTRY • Previous Articles     Next Articles

Phase Relationship, Structure and Cationic Distribution of Oxides in the Mn3O4-Fe2O3 System Synthesized at 1200 ℃

WANG Rong2, YANG Cheng-Xu1, SHI Ying-Guo3, SUN Yu-Zeng1, LI Guo-Bao1, JIN Tou-Nan2, QIN Gao-Wu3, LIAO Fu-Hui1, LIN Jian-Hua1   

  1. 1. State Key Laboratory of Rare Earth Materials Chemistry and Applications, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China;
    2. College of Material Science and Engineering, Beijing University of Technology, Beijing 100022, P. R. China;
    3. Key Laboratory for Anisotropy and Texture of Materials(Ministry of Education), Northeastern University, Shenyang 110819 , P. R. China
  • Received:2011-12-08 Revised:2012-02-13 Published:2012-04-26
  • Contact: LI Guo-Bao, JIN Tou-Nan, QIN Gao-Wu, LIN Jian-Hua E-mail:liguobao@pku.edu.cn; tnjinkim@bjut.edu.cn; qingw@smm.neu.edu.cn; jhlin@pku.edu.cn
  • Supported by:

    The project was supported by the National Key Basic Research Project of China (973) (2010CB833103) and Scientific Research Key Program of Beijing Municipal Commission of Education, China (KM201010005019).

Abstract: A series of oxides in the Mn3O4-Fe2O3 system have been synthesized at 1200 ℃ in air, followed by quenching to room temperature. Three solid solutions, Mn3-3xFe3xO4 (0.00≤x≤0.278), Mn3-3xFe3xO4(0.291≤x≤0.667), and Mn2-2xFe2xO3 (0.89≤x≤1.00), have been identified by powder X-ray diffraction (XRD). Rietveld refinement of the XRD data show that the solids belong to the hausmannite phase with the space group I41/amd, the spinel phase with the space group Fd3m, and the hematite phase with the space group R3c, respectively. Between these are two-phase regions. 57Fe Mössbauer spectra indicate that the valence state of Fe in the three solid solutions is +3; in addition, there are two crystallographically independent Fe3+ ions in the unit cells of the hausmannite and spinel phases, and one Fe3+ in the hematite phase. Analyses of 57Fe Mössbauer spectra and X-ray photoelectron spectra (XPS) revealed that a formula of Mn1-x2+Fex3+[Mnx3+Fex3+Mn2-3x3+]O4 describes the cation distribution of both the hausmannite and spinel phases, but that for the hematite phase is Mn2-2x3+Fe2x3+O3.

Key words: Phase relationship, Structure, 57Fe Mö, ssbauer spectroscopy, X-ray photoelectron spectroscopy, Cation distribution, Mn3O4, Fe2O3

MSC2000: 

  • O641