ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 35, Number 4
JKCSEZ 35(4)
August 20, 1991 

The x values and electrical conductivity of the nonstoichiometric compound NbOx have been measured in a temperature range 700℃ to 1100℃ under oxygen partial pressure of 2 × 10-1 ∼ 1 × 10-5 atm. The NbOx is a stoichiometrical compound of Nb2O5 under oxygen partial pressure higher than 1.0 × 10-2 atm at the above temperature range. The x values were found to vary between 2.48491 and 2.49900 in a temperature range 700℃ to 1100℃ under oxygen partial pressure lower than 1 × 10-3 atm. The enthalpy of the formation for x' in NbO2.50000-x'(△Hf) increased of 15.98 to 17.26 kcal/mol under the conditions. The electrical conductivity (σ) of the oxide varied from 10-4 to 10-1 ohm-1cm-1 in the above conditions. The activation energy for the conduction was about 1.7 eV. The oxygen pressure dependency of the conductivity (or 1/n value) was about -1/4. The nonstoichiometric conduction mechanism of the oxide has been discussed with the x' values, the σ values, and the thermodynamic data.