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

402
A Discussion of selected references
Table A-65: Experimental and derived results for dissolution of abhurite at 298.2 K
converted to the molality basis.
log
10(
m /m)
Sn 2 + ( mCl
− /m) I/m pH (molal basis)
− 2.068 − 0.376 0.394 1.180
− 2.091 − 0.373 0.394 1.195
− 2.147 − 0.364 0.394 1.277
− 2.181 − 0.358 0.394 1.277
− 2.179 − 0.363 0.394 1.301
− 2.313 − 0.339 0.404 1.326
− 2.295 − 0.344 0.404 1.346
The re-evaluation of these data employing the SIT formalism showed that they
are indeed consistent with the stoichiometry Sn 21 Cl 16 (OH) 14 O 6 (s), however, due to the
narrow pH range the data would be consistent with SnOHCl·H 2 O(s) as well.
This results in the following solubility constant log * 10 K s,16202621 =
ο
− (1.58 ± 0.07). and leads to (1/21) Δ fGm(Sn 21 Cl 16 (OH) 14 O 6 , cr, 298.15 K) =
− (362.68 ± 0.49) kJ·mol –1 .
Table A-66: Experimental and derived results for dissolution of abhurite at 298.2 K
converted to the molality basis and re-evaluated using the SIT formalism.
log10 a
Sn 2 + log10 aCl
− y 16202621 log * 10 K s,16202621
− 2.6419 − 0.5303 − 3.05135 − 1.5907
− 2.6641 − 0.5270 − 3.07099 − 1.5917
− 2.7185 − 0.5198 − 3.11994 − 1.5392
− 2.7514 − 0.5143 − 3.14857 − 1.5678
− 2.7424 − 0.5194 − 3.14353 − 1.5330
− 2.8844 − 0.4975 − 3.26876 − 1.6273
− 2.8669 − 0.5019 − 3.25466 − 1.5885
[1992SAS/SHO]
Correlations between standard partial molar entropies, S , of aqueous mono-, di-, and
trivalent ions at 25 °C and 1 bar and effective electrostatic radii, r e , calculated from the
corresponding crystallographic radii, r x , have been constructed for coordination
numbers from 4 to 12. An expanded set of predicted entropies based on revised
Shannon-Prewitt [1976SHA] crystallographic radii is provided. These correlations are
generalised such that they can be applied to monoatomic aqueous ions of any charge, z,
or coordination number, n.
ο
m
CHEMICAL THERMODYNAMICS OF TIN, ISBN 978-92-64-99206-1, © OECD 2012