Other
Scientific paper
Jan 1988
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1988gecoa..52..167t&link_type=abstract
Geochimica et Cosmochimica Acta, vol. 52, Issue 1, pp.167-176
Other
2
Scientific paper
High temperature reaction calorimetry has been applied in a thermochemical study of solid and liquid phases in the quasi-binary system Ag 2 S-Sb 2 S 3 . Direct synthesis calorimetry of stibnite, Sb 2 S 3 , at 880 K and 768 K, from the elements yields a mean value for the standard enthalpy of formation, H 0 f , stibnite, 298 K = -129.72 ± 3.75 kJ mol -1 ; this value is about 12 kJ mol -1 less exothermic than a previously reported value obtained by fluorine combustion calorimetry. The enthalpies of formation at 298 K of the sulfosalts -miargyrite (AgSbS 2 ) and hexagonal pyrargyrite (Ag 3 SbS 3 ) from their endmember component sulfides (Ag 2 S and Sb 2 S 3 ) were determined to be -4.1 ± 2.3 kJ mol -1 and -7.8 ± 0.8 kJ mol -1 , respectively. The enthalpy of transformation of ordered monoclinic -miargyrite to disordered cubic -miargyrite at 298 K was determined to be +8.7 ± 1.4 kJ mol -1 . If the equilibrium temperature for this transformation is equal to 650 K, this implies an entropy of transformation of about +13.3 J/K mol. Liquid mixtures of solid Ag 2 S and liquid Sb 2 S 3 at 880 K were studied by solid-liquid reaction calorimetry, and by dilution calorimetry, with pure liquid Sb 2 S 3 . Measurements of the solid-liquid enthalpies of mixing yielded the following linear expression H S - L mix / X Ag 2 S = -6.35 + 13.33 X Ag 2 S (kJ mol -1 )), based on experiments with values of X ag 2 S ranging from 0.1 to 0.86. This equation is consistent with a symmetrical, regular solution model and implies that the heat of fusion of Ag 2 S at 880 K (for X Ag 2 S = 1.00) is 6.98 kJ mol -1 . Our data yield an average value for Cp s - l , Ag 2 S of about 4 joules K -1 mol -1 . The approximate partial enthalpies of solution of liquid Sb 2 S 3 , obtained from the dilution experiments, are consistent with the expression .
Bryndzia Taras L.
Kleppa O. J.
No associations
LandOfFree
High-temperature reaction calorimetry of solid and liquid phases in the quasi-binary system Ag 2 S-Sb 2 S 3 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with High-temperature reaction calorimetry of solid and liquid phases in the quasi-binary system Ag 2 S-Sb 2 S 3, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and High-temperature reaction calorimetry of solid and liquid phases in the quasi-binary system Ag 2 S-Sb 2 S 3 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1046730