Site occupancy of Fe2+, Fe3+ and Ti4+ in titanomagnetite determined by valence-difference contrast in synchrotron X-ray resonant scattering

Maki Okube, Taro Oshiumi, Toshiro Nagase, Ritsuro Miyawaki, Akira Yoshiasa, Satoshi Sasaki, Kazumasa Sugiyama

Research output: Contribution to journalArticlepeer-review

Abstract

A synchrotron X-ray diffraction study of a single crystal of titanomagnetite shows that the cation distribution of Fe2+, Fe3+ and Ti4+ is of the inverse-spinel type. The valence-difference contrast (VDC) method of resonant scattering was applied at a wavelength of λ = 1.7441 Ã… (E = 7.1085 keV) within the pre-edge of the Fe K absorption spectrum, utilizing the large difference in the real part of anomalous scattering factors, between −7.45 and −6.50, for Fe2+ and Fe3+, respectively. The most plausible atomic arrangement in Ti0.31Fe2.69O4 obtained from our analysis is [Fe3+ 1.00]A[Fe3+ 0.38Fe2+ 1.31Ti4+ 0.31]BO4, where A and B in an AB2O4-type structure correspond to the tetrahedral and octahedral sites, respectively. This result suggests that titanomagnetite has the complete inverse-spinel structure continuously from the end-member of magnetite, even in the case of relatively high Ti content. The physical properties may be described by the NÃ

Original languageEnglish
Pages (from-to)1694-1702
Number of pages9
JournalJournal of Synchrotron Radiation
Volume25
Issue number6
DOIs
Publication statusPublished - 2018 Nov

Keywords

  • Fe K absorption edge
  • anomalous scattering
  • resonant scattering
  • single-crystal X-ray diffraction
  • titanomagnetite
  • valence-difference contrast

ASJC Scopus subject areas

  • Radiation
  • Nuclear and High Energy Physics
  • Instrumentation

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