ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 33, Number 1
JKCSEZ 33(1)
February 20, 1989 

The nonstoichiometry and electrical conductivities of Tm2O3 were studied in the oxygen pressure 2 × l0^-1 ∼ 1 × l0^-4 atm under the temperature ranges from 700 to 1100℃. The x values of TmO1.5 were varied in the ranges of 0.1004∼0.0110. The enthalpies of formation of the nonstoichiometric compounds were found to be 5.40-4.71 kcal/mole, and the average activation energy obtained from the plots of log conductivity vs. 1000/T was 1.65 eV. The PO2 dependencies of the electrical conductivity were found to be linear and closely approaximated to σα PO₂^1/5.3 in the temperature range 700∼1100℃. The nonstoichiometry and the electrical conductivity are due to trivalent metal vacancies.