Chemical Thermodynamics of Tin - Volume 12 - OECD Nuclear ...

216
IX Group 16 compounds and complexes
ο
Data for Δ fHm
(Sn 2 S 3 , cr, 298.15 K) were obtained by reaction calorimetry
[1973STO/NEK] and by Knudsen effusion/mass spectrometry ([1980WIE/CSI3] and
[1991PIA/FOG]). The data are presented in Table IX-8. The datum of [1973STO/NEK]
is questionable because auxiliary information was lacking and possible sources of error
were not addressed (editor’s comments in [1973STO/NEK2]). Rau [1965RAU]
measured decomposition/sublimation pressures of SnS, as did [1937GER/KRU] and
[1967KAR/PAS]. Data from compilations/evaluations are also given in Table IX-8.
Table IX-8: Experimental determination of the standard enthalpy of formation of
Sn 2 S 3 (cr) and data from compilations/evaluations.
Experimental measurements
Reference Method Δ fH m (Sn 2 S 3 , cr, 298.15 K)/kJ·mol –1
[1973STO/NEK] Reaction calorimetry − 266.0 ± 4.0
[1980WIE/CSI3] Knudsen effusion/mass spectrometry − 254.5 ± 6.0
[1991PIA/FOG] Knudsen effusion/mass spectrometry − 253.0 ± 2.0
[1937GER/KRU] Dissociation pressure − 264.0 ± 21.0 (3 rd law)
[1967KAR/PAS] Dissociation pressure − 239.0 ± 29.0 (2 nd law)
− 263.0 ± 21.0 (3 rd law)
[1965RAU] Decomposition/sublimation pressure − 297.5 ± 11.0
[1957SEV] Dissociation pressure − 270.1 ± 6.0
Compilations/evaluations
Reference Δ fH m (Sn 2 S 3 , cr, 298.15 K)/kJ·mol –1
[1974MIL] − 264.0 ± 21.0 *
[1993BAR] − 263.592
[1999BIN/MIL] − 263.6
[1977BAR/KNA] − 263.0
* Value selected by this review.
The selected heat capacity of Sn 2 S 3 (cr) is given by Eq. (IX.4), with the
standard error of estimate in C ο = ± 1.1 J·K –1·mol –1 p,m
,
C ο p,m (Sn 2 S 3 , cr, 298.15 K) = (118.5 ± 1.6) J·K –1·mol –1 .
The selected standard entropy of Sn 2 S 3 is
S ο –1
m (Sn 2 S 3 , cr, 298.15 K) = (163.6 ± 6.0) J·K
–1·mol
and the selected standard enthalpy of formation is
which yields:
Δ (Sn 2 S 3 , cr, 298.15 K) = − (264.0 ± 21.0) kJ·mol –1 ,
fH ο
m
Δ ο
f G m (Sn 2S 3 , cr, 298.15 K) = − (253.6 ± 21.1) kJ·mol –1 ,
CHEMICAL THERMODYNAMICS OF TIN, ISBN 978-92-64-99206-1, © OECD 2012