Materials Research Bulletin, Vol.31, No.2, 141-146, 1996
An Electron-Density Residual Study of Alpha-Ferric Oxide
The residual electron density distribution in alpha-ferric oxide (Fe2O3; natural hematite) has been studied with single-crystal X-ray diffraction methods. A residual electron density double peak of 0.55 Angstrom height is situated along the c-axis between face-sharing Fe’s, indicating metal-metal interaction. Residuals suggesting d-electrons were found around Fe. There are also interstitial residuals arranged around Fe hexagonally in a plane perpendicular to the c-axis. These features conform rather to directions related to the Fe neighbors than the coordinated oxygens. [393 equivalent-averaged reflexions, R values; conventional refinement with harmonic parameters : 0.0088, with scattering factor refinement : 0.0069; incorporation of anharmonic parameters did not lower the R value significantly.]