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

Chapter XI
XI Group 14 compounds and
complexes
XI.1 Aqueous tin thiocyanato complexes Equation Section 11
XI.1.1 Aqueous Sn(II) thiocyanates
The formation of thiocyanato complexes of tin(II) in aqueous solution has been reported
in [1961GOL/OGN], [1976SAM/LYA] and [1980FED/BOL]. The equilibrium
constants for the reactions
are summarised in Table XI-1.
Sn 2+ + q SCN – 2−
SnSCN q
q
(XI.1)
2−
Table XI-1: Experimental formation constants of the species SnSCN q .
log 10 β q
Method Ionic media t /°C reported Recalculated (a) Accepted (b) Reference
Sn 2+ + SCN – SnSCN +
Ise-Sn 2.2 M NaClO 4 20 1.17 0.70 ± 0.01 0.65 ± 0.30 [1961GOL/OGN]
Ise-Sn 1.0 M NaClO 4 25 1.03 ± 0.07 [1976SAM/LYA]
Ise-Sn 0.5 M NaClO 4 25 1.32 ± 0.02
[1980FED/BOL]
1.0 M NaClO 4
3.0 M NaClO 4
25
25
0.83 ± 0.06
0.90 ± 0.10
0.81 ± 0.50
0.83 ± 0.50
Sn 2+ + 2 SCN – Sn(SCN) 2 (aq)
Ise-Sn 2.2 M NaClO 4 20 1.77 1.65 ± 0.01 1.55 ± 0.30 [1961GOL/OGN]
Ise-Sn 1.0 M NaClO 4 25 1.57 ± 0.03 [1976SAM/LYA]
Ise-Sn 1.0 M NaClO 4 25 1.10 ± 0.10
[1980FED/BOL]
3.0 M NaClO 4 25 1.40 ± 0.10
Sn 2+ + 3 SCN – SnSCN −
3
Ise-Sn 2.2 M NaClO 4 20 1.72 [1961GOL/OGN]
Ise-Sn 3.0 M NaClO 4 25 1.53 ± 0.10 [1980FED/BOL]
(a) ` Re-evaluated values, see Appendix A.
(b) Accepted values converted 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.
q
CHEMICAL THERMODYNAMICS OF TIN, ISBN 978-92-64-99206-1, © OECD 2012