The La{sub 2}S{sub 3}-LaS{sub 2} system: Thermodynamic and kinetic study
- Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences, 3, Acad. Lavrentyev Pr., Novosibirsk 630090 (Russian Federation)
A detailed thermodynamic study of the LaS{sub 2}-La{sub 2}S{sub 3} system in the temperature range 350-1000 {sup o}C was performed, starting from high quality crystals LaS{sub 2} as the highest polysulfide in the system, and using a sensitive static tensimetric method with a quartz Bourdon gauge and a membrane as a null-point instrument. The p{sub S}-T-x diagram obtained has shown that the phase region covering the composition between LaS{sub 2} and La{sub 2}S{sub 3}, which was previously described as a single grossly nonstoichiometric phase, consists of three discrete stoichiometric phases, LaS{sub 2.00}, LaS{sub 1.91}, and LaS{sub 1.76}, where compositions could be determined with an accuracy of {+-}0.01 f.u. The thermodynamic characteristics of evaporation of the polysulfides as well as standard heat of LaS{sub 2} formation were calculated. The role of kinetics in the formation of ordered superstructures of sulfur-poorer polysulfides with different formal concentration of vacancies is considered. - Graphical abstract: The p{sub S}-T stability fields for La-polysulfides in the concentration range between LaS{sub 2} and La{sub 2}S{sub 3}.
- OSTI ID:
- 21421571
- Journal Information:
- Journal of Solid State Chemistry, Vol. 183, Issue 8; Other Information: DOI: 10.1016/j.jssc.2010.05.026; PII: S0022-4596(10)00229-X; Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
DIAGRAMS
EVAPORATION
HEAT
KINETICS
LANTHANUM SULFIDES
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE RANGE 0400-1000 K
TEMPERATURE RANGE 1000-4000 K
THERMODYNAMIC PROPERTIES
VACANCIES
CHALCOGENIDES
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
ENERGY
INFORMATION
LANTHANUM COMPOUNDS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
POINT DEFECTS
RARE EARTH COMPOUNDS
SULFIDES
SULFUR COMPOUNDS
TEMPERATURE RANGE