Crystal structure of β-Fe2O3 and topotactic phase transformation to α-Fe2O3

Teruaki Danno, Daisuke Nakatsuka, Yoshihiro Kusano, Hiroshi Asaoka, Makoto Nakanishi, Tatsuo Fujii, Yasunori Ikeda, Jun Takada

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31 Citations (Scopus)

Abstract

β-Fe2O3 is the scarce polymorph of Fe 2O3 phases and is transformed easily into α-Fe 2O3 at high temperature. However, its crystal structure and the transformation mechanism to α-Fe2O3 are still unclear because of the difficulty in obtaining monophasic β-Fe 2O3 crystals. We established a synthesis method of the monophasic β-Fe2O3. It was synthesized by a two-step reaction: heating a mixture of Na2SO4 and Fe 2(SO4)3 in air at 250 C to form NaFe(SO 4)2, and subsequent heating the resultant phase with NaCl in air at 500 C. The crystal structure was refined to a bixbyite-type cubic structure (Ia3Ì...) with a = 9.4039(1) Å by the Rietveld method. Single crystalline β-Fe2O3 particles of approximately 1 μm in size were topotactically transformed into single α-Fe 2O3 crystals. Electron diffraction analysis revealed the crystallographic orientation relationships between β-Fe2O 3 and α-Fe2O3 to be [100] β//[0001]α, [010]β// [101Ì...0]α, and [001]β//[1Ì... 21Ì...0]α.

Original languageEnglish
Pages (from-to)770-774
Number of pages5
JournalCrystal Growth and Design
Volume13
Issue number2
DOIs
Publication statusPublished - Feb 6 2013

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics

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    Danno, T., Nakatsuka, D., Kusano, Y., Asaoka, H., Nakanishi, M., Fujii, T., Ikeda, Y., & Takada, J. (2013). Crystal structure of β-Fe2O3 and topotactic phase transformation to α-Fe2O3. Crystal Growth and Design, 13(2), 770-774. https://doi.org/10.1021/cg301493a