KCS Publications

HOME > Search > Browsing(BKCS) > Archives

Bulletin of the Korean Chemical Society (BKCS)

ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 15, Number 1
BKCSDE 15(1)
January 20, 1994

Title	Nonstoichiometry of the Terbium Oxide
Author	Chul Hyun Yo, Kwang Sun Ryu, Eun Seok Lee*, Keu Hong Kim
Keywords
Abstract	The x values of nonstoichiometric chemical formula, Tb4O7-δ or TbO1.5+x, have been determined in temperature range from 600 ℃ to 1000 ℃ under oxygen partial pressure of 2 × 10-1 to 1 × 10-5 atm by using quartz microbalance. The x values varied from 0.0478 to 0.1964 in the above conditions. The enthalpy of formation for x' in TbO1.5+(0.25-xO-x'), ΔHf, was 4.93-3.40 kcal mol-1 and the oxygen partial pressure dependence was -1/8.80∼-1/11.8 under these conditions. The electrical conductivity of the TbO1.5+x was measured under the same conditions and the values varied from about 10-3 to 10-6 Ω-1cm-1 within semiconductor range. The activation energies for the conduction increase with oxygen partial pressure from 0.83 to 0.89 eV under the above conditions. The l/n values obtained from the oxygen pressure dependence of the conductivity are 1/4.4-1/5.2. The conduction mechanism, defect structure, and other physical properties of the oxides are dicussed with the x values, the electrical conductivity values, and the thermodynamic data.
Page	33 - 36
Full Text	PDF

How to access to the WOL for The Bulletin of the Korean Chemical Society ?

The Bulletin of the Korean Chemical Society will be co-published with Wiley-VCH from 2015 towards. The online version of the Journal will thus be available on Wiley Online Library, Wiley(-VCH)'s global online platform.

KCS members can get a free online access to the Bulletin of the Korean Chemical Society in WOL.

Free Access to WOL