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

VIII.3 Aqueous halide complexes
169
Figure VIII-16: Extrapolation to I = 0 of the experimental data for reaction Sn 2+ + F –
SnF + in NaClO 4 media (: experimental data from: [1985DJO/ZMB], [1976SCH/CRO]
and [1970BON/TAY]).
6
Sn 2+ + F – SnF +
log 10
β 1
+ 4D
5
0 1 2 3
I / mol·kg –1
A similar treatment (cf. Figure VIII-17) of the accepted data for Reaction
((VIII.9), q = 2) resulted in the selected value of
ο
log10 β
2
((VIII.9), q = 2, 298.15 K) = (8.89 ± 0.21).
From the slope in Figure VIII-17, Δε((VIII.9), q = 2) = − (0.23 ± 0.09)
kg·mol –1 and ε(SnF 2+ (aq), NaClO 4 (aq)) = (0.01 ± 0.10) kg·mol –1 (≈ 0.00 kg·mol –1 ) can
be derived.
Although there is no doubt concerning the formation of the trifluoro species,
the log10 β 3 values reported in [1970BON/TAY] and [1985DJO/ZMB] for NaClO 4
media are rather scattered (Figure VIII-18). Since the experiments of the above papers
seem to be equally reliable, the inherent uncertainties of the reported/re-evaluated
constants were considerably increased (see Appendix A). The SIT treatment of the five
available experimental data for NaClO 4 media resulted in
ο
log10 β
3
((VIII.9), q = 3, 298.15 K) = (11.5 ± 1.0).
CHEMICAL THERMODYNAMICS OF TIN, ISBN 978-92-64-99206-1, © OECD 2012