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

368
A Discussion of selected references
Figure A-41: SIT analysis of data from [1979VAS/GLA].
E - (k/2)·[log(m Sn
4+·m –1 Sn 2+·m–2 H + –10·D] / V
0.275
0.274
0.273
0.272
0.271
0.270
exp. data [1979VAS/GLA] corrected
SIT analysis
confidence limits
E°(Sn 4+ /Sn 2+ ) = (0.2740 ± 0.0010) V
0 1 2 3 4 5
m (ClO 4 – + Cl – )
This re-evaluation simply attempted to interpret the results presented in
[1979VAS/GLA] correctly. In order to perform a SIT analysis the concentrations listed
in Table A-42 were converted into molalities, see Table A-43. As shown in Figure A-41
the extrapolation to m − −
(ClO4
+ Cl ) = 0 clearly resulted in a different value, due to the sign
error mentioned above. In contrast to the results of [1978FAT/ROU] and
[2009GAJ/SIP] who found highly stable Sn(IV) chlorido complexes Vasil’ev et al.
disregarded those altogether in their ionic media. Moreover the Sn(IV) hydrolysis
constants of [1971NAZ/ANT] are approximate estimates only. Consequently
o 4+
2+
E (Sn / Sn ) = (0.2740 ± 0.0010) V was not used in this review for calculating the
finally selected mean value.
CHEMICAL THERMODYNAMICS OF TIN, ISBN 978-92-64-99206-1, © OECD 2012