Mixed crystal formation and structural studies in the mullite-type system Bi 2Fe 4O 9Bi 2Mn 4O 10
The limits of metal cation substitution and distribution in the sequence Bi 2Fe 4O 9Bi 2Mn 4O 10 have been investigated by solid state synthesis, X-ray powder diffraction, and Mössbauer spectroscopy. Rietveld refinements conducted for the entire range along the join indicate the structures are orthorhombic with space group Pbam, with partial transition-metal site disorder confirmed and detailed by Mössbauer spectroscopy. Single-phase regions are found near each end-member and a two-phase region is observed at intermediate compositions, extending from about x=1 to 3, according to the general formula of the mixed crystals Bi 2Fe 4-xMn xO 10-δ. An incorporation of Mn at octahedral sites replacing Fe is taken into account for the Bi 2Fe 4O 9-related side of the system. Charge compensation is believed to be effected by addition of O, which gives rise to the formation of FeO 5 pyramids. At the Bi 2Mn 4O 10-related side of the system, substitution of pyramidal Mn 3 by Fe 3 is envisaged. © 2011 Elsevier Inc. All rights reserved.
Journal of Solid State Chemistry
Digital Object Identifier (DOI)
Kann, Auletta, J. T., Hearn, E. W., Weber, S.-U., Becker, K. D., Schneider, H., & Lufaso, M. W. (2012). Mixed crystal formation and structural studies in the mullite-type system Bi2Fe4O9–Bi2Mn4O10. Journal of Solid State Chemistry, 185, 62–71. https://doi.org/10.1016/j.jssc.2011.10.046