The effective charge number, Z*, was measured for various compositions of TiO2−x at 1050C. It was determined from the value of the stationary chemical potential gradient of oxygen in TiO2−x subjected to a known electrical potential gradient. The results (Z* ≈ 3) suggested that interstitial titanium ions Ti3+ were responsible for the diffusional process and called into question the importance of the interstitial Ti4+ ions for the description of the defect structure of this oxide.

Isothermal Transport in TiO2-x. Part I. Electromigration in TiO2-x. Ait-Younes, N., Millot, F., Gerdanian, P.: Solid State Ionics, 1984, 12, 431-6