Thermodynamic Study of the SmS 2-SmS 1.5System
Abstract
A detailed thermodynamic study of the SmS 2-SmS 1.5system in the temperature range 350-1000°C was performed using high-quality crystals of the highest Sm-polysulfide and a sensitive static tensimetric method, a quartz Bourdon gauge with a membrane as a null-point instrument. The P- T- xdiagram obtained has shown that the phase region covering the composition range SmS 2.00-SmS 1.82, which was previously described as a single grossly nonstoichiometric phase, consists of three discrete stoichiometric phases, SmS 1.900, SmS 1.893, and SmS 1.863. The polysulfide compositions were evaluated from the tensimetric data with an accuracy of ±0.001 f. u. The thermodynamic parameters of incongruent sublimation were calculated for each polysulfide, and then the standard heats of formation were estimated for these compounds.
- Publication:
-
Journal of Solid State Chemistry France
- Pub Date:
- February 1999
- DOI:
- 10.1006/jssc.1998.7802
- Bibcode:
- 1999JSSCh.142..261V