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

A Discussion of selected references
261
unknown amount of chloride ions may have contributed to the solubility of “Sn(OH) 2 ”
or Sn 6 (OH) 4 O 4 (cr).
Figure A-3: log10 K s,3
(A.9) vs. m +
Na
(: experimental; solid line: linear regression
log K = − (0.34 ± 0.18)); dashed lines: confidence limits).
( 10 s,3
0.0
-0.1
Sn(OH) 2
(s) + OH – Sn(OH) –
3
-0.2
-0.3
log 10
K s 3
-0.4
-0.5
-0.6
-0.7
-0.8
0.000 0.005 0.010 0.015 0.020 0.025 0.030 0.035
m (Na + ) / mol·dm –3
[1906WEI]
Solubility of a series of sulfides was determined in water at (18 ± 0.03) °C. Solute
concentration was calculated from electrical conductivities using the values for ion
mobilities. Conductivity of pure water was less than 1.5 × 10 –6 . The calculations were
based on the following hydrolytic reactions:
SnS + 2 H 2 O(l) → Sn 2+ + H 2 S + 2 OH –
SnS 2 + 2 H 2 O(l) → Sn 2+ + 2 OH – + H 2 S + S.
The following ion mobility values had been used (no units given): OH – = 174;
0.5 Sn 2+ = 61.5. The conductivity contribution of dissolved H 2 S was neglected. Separate
conductivity measurements of H 2 S solutions gave support for this approximation.
SnS was prepared by heating of precipitated tin sulfide to 1273 K in a stream
of pure nitrogen. Chemical analysis of black well crystallised product showed an excess
of tin of about 1 mass-%. For SnS 2 a sample of “Musivgold” from Schuchardt was used.
CHEMICAL THERMODYNAMICS OF TIN, ISBN 978-92-64-99206-1, © OECD 2012