Structural vacancies were directly observed in non-stoichiometric ordered titanium monoxide by using high-resolution transmission electron microscopy under a magnification of 4 x 106. The observation of structural vacancies became possible due to their ordering and the formation of continuous vacancy channels in certain crystallographic directions. Micro-diffraction was employed to orient the sample in the direction permitting the observation of vacancy channels. Transmission electron microscopy providing a magnification of tens of thousands of times revealed that titanium monoxide grains do not contain cracks and macropores and confirmed that the free volume detected picnometrically in the titanium monoxide was concentrated in structural vacancies on the Ti and O sub-lattices.

Observation of Structural Vacancies in Titanium Monoxide Using Transmission Electron Microscopy. Valeeva, A.A., Tang, G., Gusev, A.I., Rempel, A.A.: Physics of the Solid State, 2003, 45[1], 87-93