Thermodynamic Study of the SmS2–SmS1.5System

✍ Scribed by I.G. Vasilyeva; E.I. Belyaeva

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 162 KB
• Volume: 142
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1998.7802

✦ Synopsis

A detailed thermodynamic study of the SmS 2 -SmS 1.5 system in the temperature range 350-1000°C was performed using highquality 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-x diagram 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.