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

VIII.3 Aqueous halide complexes
193
thiocyanato complexes, too, therefore the equilibrium data for the chlorido-thiocyanato
complexes are also enumerated in Table VIII-13. Both in [1975FED/BOL] and
[1980FED/BOL], the NaClO 4 medium was entirely replaced during the measurements
of the ternary complexes, inducing considerable changes in the activities. The
re-evaluation of the pontentiometric data reported in [1975FED/BOL] and
[1980FED/BOL] was unsuccessful, probably due to the low precision of the graphically
presented experimental data. Therefore, the data listed in Table VIII-13, although
informative, cannot be used to derive seleced values.
Table VIII-13: Experimental formation constants of the mixed halogeno complexes of
tin(II).
Method Ionic media t/°C log10
β q
Reference
Reported Recalculated (a) Accepted (b)
Sn 2+ + Cl – + Br – SnClBr(aq)
Ise-Sn 0.5 M NaClO 4 25 2.13 ± 0.13
[1975FED/BOL]
1.0 M NaClO 4
3.0 M NaClO 4
4.0 M NaClO 4
6.0 M NaClO 4
25
25
25
25
1.64 ± 0.09
1.93 ± 0.03
2.13 ± 0.04
2.40 ± 0.05
Sn 2+ + 2 Cl – + Br – SnCl 2 Br –
Ise-Sn 3.0 M NaClO 4 25 1.98 ± 0.03
[1975FED/BOL]
4.0 M NaClO 4
6.0 M NaClO 4
25
25
2.44 ± 0.10
3.73 ± 0.06
Sn 2+ + Cl – + 2 Br – SnClBr −
2
Ise-Sn 3.0 M NaClO 4 25 1.37 ± 0.15
[1975FED/BOL]
4.0 M NaClO 4
6.0 M NaClO 4
25
25
2.19 ± 0.10
3.43 ± 0.09
Sn 2+ + Cl – + SCN – SnCl(SCN)(aq)
Ise-Sn 0.5 M NaClO 4 25 1.90 ± 0.10
[1980FED/BOL]
1.0 M NaClO 4
3.0 M NaClO 4
25
25
1.51 ± 0.06
1.87 ± 0.10
Sn 2+ + 2 Cl – + SCN – SnCl 2 (SCN) –
Ise-Sn 3.0 M NaClO 4 25 2.18 ± 0.06 [1980FED/BOL]
Sn 2+ + Cl – + 2 SCN – SnClSCN −
2
Ise-Sn 1.0 M NaClO 4 25 0.78 ± 0.10
[1980FED/BOL]
3.0 M NaClO 4 25 1.91 ± 0.10
(a) Re-evaluated values, see Appendix A.
(b) Accepted values corrected to molal scale. The accepted values reported in Appendix A are expressed on
the molar or molal scales, depending on which units were used originally by the authors.
CHEMICAL THERMODYNAMICS OF TIN, ISBN 978-92-64-99206-1, © OECD 2012