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

96 VI Simple tin aqua ions
given in Table A-33 Obviously only Δ r H (VI.16) and Δ r H (VI.17) could be evaluated
with sufficient accuracy to justify extrapolation to infinite dilution.
Recalculation with a set of constants, selected by this review, is in principle
possible only when the composition of the solutions used for calorimetry can be
ascertained. This is the case for the experimental data at 25 °C listed in
[1973VAS/VAS], but not for those at 10 °C presented graphically in [1976VAS/KOK].
ο
For the evaluation of Δ fHm
(Sn 2+ , 298.15 K) only Reaction (VI.16) and (VI.19) are
relevant. Consequently extrapolation of Δ r H (VI.16) for SnCl 2(cr) and Δ r H (VI.19) for
SnCl 2·2H 2 O(cr) to I → 0 was based on 1) the data listed in Table VI-3 for 25 °C taken
from [1976VAS/KOK] and 2) the values of Δ r H (VI.16) and Δ r H (VI.19) recalculated
in this review and listed in Table VI-4.
Table VI-3: Enthalpies of Reactions (VI.16) and (VI.19) at 25 °C from
[1976VAS/KOK].
I c /mol·dm –3
(HClO 4 )
I m /mol·kg –1
(HClO 4 )
SnCl 2 (cr)
r H SnCl 2·2H 2 O(cr)
r H 0.5 0.5133 − 10.251 ± 1.004 7.573 ± 0.209
1.0 1.0508 − 9.163 ± 0.335 8.745 ± 0.335
2.0 2.2038 − 6.402 ± 0.377 11.966 ± 0.167
3.0 3.4713 − 3.012 ± 0.418 15.188 ± 0.209
Table VI-4: Enthalpies of Reactions (VI.16) and (VI.19) at 25 °C from
[1973VAS/VAS].
I c /mol·dm –3
(HClO 4 )
I m /mol·kg –1
(HClO 4 )
SnCl 2 (cr)
r H SnCl 2·2H 2 O(cr)
r H 0.20 0.2025 − 13.0 ± 0.2 5.3 ± 0.7
0.49 0.5027 7.4 ± 0.2
1.02 1.0722 − 9.4 ± 0.3 8.7 ± 0.5
1.96 2.1545 − 6.6 ± 0.4 11.6 ± 0.4
2.93 3.3790 − 3.0 ± 0.5 14.6 ± 0.6
The SIT approach to extrapolate enthalpies of reaction in electrolyte systems to
infinite dilution is described in [1997ALL/BAN] and [1996PLY/GRE], who criticised
the methods proposed by [1967VAS] and [1978VAS/YAS2]. This evoked a controversy
between Vasil’ev [1997VAS] and Plyasunov and Grenthe [1998PLY/GRE]. The
present review agrees with the thermodynamic argument put forward by
[1996PLY/GRE] and adopts the SIT approach. For a comparison between Vasil’ev’s
[1967VAS], Vasil’ev and Yasinskii’s [1978VAS/YAS] and the SIT method, see
CHEMICAL THERMODYNAMICS OF TIN, ISBN 978-92-64-99206-1, © OECD 2012