Mixed crystal formation and structural studies in the mullite-type system Bi 2Fe 4O 9Bi 2Mn 4O 10

Document Type

Article

Publication Date

1-1-2012

Abstract

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.

Publication Title

Journal of Solid State Chemistry

Volume

185

First Page

62

Last Page

71

Digital Object Identifier (DOI)

10.1016/j.jssc.2011.10.046

ISSN

00224596

E-ISSN

1095726X

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