High resolution electron microscopy of TiO2·7Nb2O5

The defect structure of TiO₂·7Nb₂O₅ has been examined at about 0.3 nm resolution in an electron microscope. Under suitable conditions of crystal orientation and objective lens defocus, the contrast in images from very thin fragments can be interpreted directly in terms of structure. Proposed structures for Wadsley intergrowth defects and displacements are confirmed, and new observations of complex fault bands and grain boundaries are described. Microdomains of TiNb₁₄O₃₇, with the structure predicted by Wadsley, have also been found in this material.