Electron density study of spinels: Magnesium titanium oxide (Mg2TiO4)

The electron density distribution in magnesium titanium oxide spinel [composition Mg2TiO4 tetrahedral site T = Mg, octahedral site X = Mg, Ti (equal amounts) for general formula TX2O4] has been studied with single-crystal X-ray diffraction methods through scattering factor refinement procedures. In the refinement with harmonic parameters, a positive residual region up to +0.25e /إ3 in height encircles oxygen in the hemisphere directed towards the T-site, along with weak residuals assuming octahedral arrangements around the X-site. These residuals almost completely disappear with anharmonic refinement. Another residual +0.20 e/إ3 in height is situated near the X4O4 cuboidal unit. [153 equivalent-averaged reflexions, R = 0.0077 (harmonic refinement), R = 0.0059 (anharmonic refinement)]