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

IX.1 Sulfur compounds and complexes 219
Table IX-12: Experimental determination of the standard enthalpy of formation of
SnS 2 (cr) after [1991GUR/VEY].
ο
Reference Method T/K data points/ Δ
fH
m
(SnS 2 , cr, 298.15 K)/
experiments
kJ·mol –1
Second law Third law
[1937GER/KRU] Static
923 – 973 3 − 148 ± 13 − 161 ± 13
2 SnS 2 (cr) Sn 2 S 3 (cr) +
½ S 2 (g)
[1957SEV] Transpiration
623 – 773 4 − 178 ± 17 − 172 ± 12
2 SnS 2 (cr) + H 2 (g)
Sn 2 S 3 (cr) + H 2 S(g)
[1967KAR/PAS] Static
773 – 1020 9 − 160 ± 14
SnS 2 (cr) products (a)
[1980WIE/CSI] Knudsen effusion 678 – 820
− 154.6 ± 4.0 − 157.5 ± 4.0
[1980WIE/CSI3]
(b)
2 SnS 2 (cr) 2 SnS(cr) +
S 2 (g)
[1973MOR/STO] Calorimetry
? 8 − 123.0 ± 10.0
2 SnS 2 (cr) + 4 Zn(cr)
2 Sn(cr) + 4 ZnS(cr)
[1991PIA/FOG] Knudsen effusion 689 − 807 28 − 148 ± 2
2 SnS 2 (cr) 2 SnS(cr) +
S 2 (g)
(a) The reaction scheme used by [1967KAR/PAS] was: 4 SnS 2 (cr) 2 Sn 2 S 3 (cr) + S 2 (g); 6 Sn 2 S 3 (cr)
4 Sn 3 S 4 (cr) + S 2 (g); 2 Sn 3 S 4 (cr) 6 SnS(cr) + S 2 (g).
(b) The equilibrium constants used in calculation were obtained by combination of those for the following
reactions: 2 SnS 2 (cr) Sn 2 S 3 (cr) + ½ S 2 (g), 678 − 798 K, 42 points Sn 2 S 3 (cr) 2 SnS(cr) + ½ S 2 (g),
677 − 820 K, 48 points.
[1991GUR/VEY] recalculated the enthalpy of formation using the original raw
data of [1937GER/KRU], [1957SEV], [1967KAR/PAS], [1980WIE/CSI] and
[1973MOR/STO]. They used a consistent set of auxiliary data for the thermodynamic
properties of SnS(cr), Sn 2 S 3 (cr), H 2 S(g), S 2 (g) and ZnS(cr). The imputed compounds
Sn 3 S 4 and Sn 4 S 5 , used by some investigators, were not considered. The only data not
consistently treated were those of [1991PIA/FOG], since these appeared too late to be
considered by [1991GUR/VEY].
In their evaluation, [1991GUR/VEY] opted to combine both calorimetric and
ο
gas-phase equilibrium data and gave as their recommended datum: Δ
fH
m(SnS 2 , cr,
298.15 K) = − (142 ± 15) kJ·mol –1 .
Since the present evaluation dispenses with the calorimetric datum, the selected
value will be more negative (Table IX-13).
CHEMICAL THERMODYNAMICS OF TIN, ISBN 978-92-64-99206-1, © OECD 2012