Thermochemical study of the phase reaction TbO/sub 1. 5 + x/ + (3/28 - x/2) O/sub 2/. -->. (1/7)Tb/sub 7/O/sub 12/

Journal Article · Sun Mar 15 04:00:00 EST 1981 · J. Solid State Chem.; (United States)

DOI:https://doi.org/10.1016/0022-4596(81)90010-4· OSTI ID:6469464

Inaba, H; Navrotsky, A; Eyring, L

The heat of reaction and equilibrium pressure for the oxidation reaction TbO/sub 1.5 + x/ + (3/28 - x/2)O/sub 2/ ..-->.. (1/7)Tb/sub 7/O/sub 12/ have been measured by means of a Tian-Calvet-type calorimeter and a thermal balance. The results of the weight measurement show a reproducible hysteresis loop. The heat of reaction has been measured along the oxidation branch of the hysteresis loop. The partial molar enthalpy indicates four distinct compositional regions. First, the TbO/sub 1.5 + x/ region which can be described in terms of a point defect model and strong interaction between neighboring excess oxygen atoms. Second, the region between TbO/sub 1/ /sub 54/ and TbO/sub 1/ /sub 61/ is interpreted as the intrinsic hysteresis region and discussed in terms of the regular solution model. Third, the region between TbO/sub 1/ /sub 61/ and TbO/sub 1/ /sub 70/ is recognized as a pseudophase region. Fourth, a region of eta phase exists in which the partial thermodynamic quantities can be compared with those of CeO/sub 1/ /sub 714/, PrO/sub 1/ /sub 714/, and TbO/sub 1/ /sub 714/. The partial molar enthalpy was also measured for a scanning loop which is also interpreted in terms of the four regimes.

• Research Organization: Arizona State Univ., Tempe
• OSTI ID: 6469464
• Journal Information: J. Solid State Chem.; (United States), Journal Name: J. Solid State Chem.; (United States) Vol. 37:1; ISSN JSSCB
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
CHALCOGENIDES
CHEMICAL REACTIONS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
ENTHALPY
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
POINT DEFECTS
RARE EARTH COMPOUNDS
REACTION HEAT
TERBIUM COMPOUNDS
TERBIUM OXIDES
THERMODYNAMIC PROPERTIES