The double perovskite oxide Sr2CrNbO6 has a cubic structure according to powder X-ray diffraction. After reducing in CO, Sr2CrNbO6 still exhibited a cubic structure refined by Rietveld technique. The TG analysis indicated that Sr2CrNbO6 loses 0.127 oxygen per formula unit from 400 to 700 degrees C in H-2. The morphology and compositions of this ceramic did not significantly change on reduction. The conductivities in various atmospheres were varied from 0.015 to 0.039 S cm(-1) at 800 degrees C. The conductivity exhibits a small oxygen partial pressure dependence in oxygen partial pressure range of 1-10(-16) atm, and this may be interpreted to reflect slow equilibration kinetics with decreasing oxygen activity. (C) 2008 Elsevier B.V. All rights reserved.