Experimentally determined thermodynamic properties of schapbachite (α-AgBiS2) below T = 700 K

Fiseha Tesfaye*, Pekka Taskinen

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

11 Citations (Scopus)

Abstract

Thermodynamic properties of schapbachite (α-AgBiS2) in the phase assemblage α-AgBiS2-AgBi3S5-Bi have been studied by an EMF-technique. The EMF-measurements were made on the galvanic cell Pt(-)|Ag|AgI|AgBiS2 + AgBi3S5 + Bi|C|Pt(+), over the temperature range from (429 to 699) K. According to the EMF vs. temperature relations obtained, the enthalpy of the phase transformation from β-AgBi1+xS2 to α-AgBi 1+xS2, at T = (465.55 ± 5) K, was calculated to be (7.3 ± 2.1) kJ · mol-1. New experimentally determined thermodynamic properties of the bismuth-saturated schapbachite (α-AgBi1+xS2), for each temperature region of the stable phases Bi(s) and Bi(l), were generated and analysed in detail. Based on the experimental results, Gibbs free energies of sulfidation reactions including Ag, Bi(l), S2(g), Ag2S and Bi2S3 to produce the bismuth-saturated schapbachite (α-AgBi1+xS2) have been evaluated. It has been observed that within the temperature range from (474 to 680) K, schapbachite saturated with bismuth (α-AgBi1+xS 2) is thermodynamically more stable than the stoichiometric schapbachite (α-AgBiS2).

Original languageEnglish
Pages (from-to)219-226
Number of pages8
JournalJournal of Chemical Thermodynamics
Volume70
DOIs
Publication statusPublished - Mar 2014
MoE publication typeA1 Journal article-refereed

Keywords

  • Electromotive force (EMF)
  • Saturation
  • Schapbachite
  • Solid solubility
  • Thermodynamic properties

Fingerprint Dive into the research topics of 'Experimentally determined thermodynamic properties of schapbachite (α-AgBiS<sub>2</sub>) below T = 700 K'. Together they form a unique fingerprint.

Cite this