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 Î» = 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 âˆ’7.45 and âˆ’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.
- anomalous scattering
- Fe K absorption edge
- resonant scattering
- single-crystal X-ray diffraction
- valence-difference contrast