A neutron diffraction investigation of the structure of vitreous germania

Abstract

Neutron diffraction techniques have been employed to obtain an accurate high-resolution real space correlation function for vitreous GeO 2. The GeO bond length is found to be 1.739 Å and the rms bond length variation 0.048 Å. The distribution of intertetrahedral GeÔGe angles is narrower than the equivalent distribution for vitreous SiO 2, but the OĜeO angles within the basic tetrahedral GeO 4 structural units appear to be more distorted - in line with a similar trend found for the corresponding α-quartz crystalline polymorphs. Structural (quasi-crystalline) models based on α-quartz and α-cristobalite GeO 2 are rejected in that they fail to account for the continuous distribution of bond and torsion angles found in the glass.