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

A Discussion of selected references
401
[1991GUR/VEY2]
Companion volume to [1991GUR/VEY]. Contains tables of recommended values of
elemental tin (from 100 to 5000 K), SnS (from 100 to 6000 K) and SnS 2 (from 100 to
6000 K) according to evaluations in [1991GUR/VEY].
[1991KHR/ZAP]
Mössbauer spectral parameters were used to estimate the speciation of 0.05 - 0.01M
SnCl 4 in 0.2 to 1 M HCl solutions. The identified mixed complexes are SnCl 5 (OH) 2– ,
2
SnCl
4(OH) − 2
2
, SnCl
3(OH) −
2
3
and SnCl
2(OH) − 4
. For example, the two major species
2
(≈ 30 - 35%) in 1 M HCl solution of tin(IV) are the complexes SnCl
4(OH) −
2
and
SnCl (OH) − .
2
3 3
[1992EDW/GIL]
The true formula of abhurite is Sn 21 Cl 16 (OH) 14 O 6 . Basic tin(II) chloride was synthesised
following two reported methods [1963DON/MOS] and [1984ICH/TAK]. Its powder
diffraction patterns were found identical with the mineral abhurite. A solubility constant
for this phase was determined at 298.15 K. For the reaction
log
*
10 s,162026
Sn 21 Cl 16 (OH) 14 O 6 (s) + 26 H + 21 Sn 2+ + 16 Cl – + 20 H 2 O(l)
K = − (31.9 ± 0.7) was found. The uncertainty assigned is 1σ.
The concentrations of Sn 2+ and Cl – given in Table A-64 were calculated by the
authors using the COMICS program and stability constants for chlorido and hydroxido
complexes of tin(II) and sodium ions from [1976BAE/MES] and [1976SMI/MAR].
Table A-64: Experimental and derived results for dissolution of abhurite at 298.2 K.
1000·[Sn 2+ ]/M 10·[Cl – ]/M I/M pH (molar basis)
8.471 4.163 0.390 1.184
8.037 4.198 0.390 1.199
7.061 4.286 0.390 1.281
6.530 4.341 0.390 1.281
6.681 4.294 0.390 1.305
4.812 4.533 0.400 1.330
5.020 4.490 0.400 1.350
For converting these results to the molality basis, see Table A-65, the ionic
medium was considered to consist of I M NaCl (m/c = 1.00975, interpolated according
to Table II-5) and [Sn 2+ ] as well as [Cl – ] were accepted as listed above (Table 2 of
[1992EDW/GIL]).
CHEMICAL THERMODYNAMICS OF TIN, ISBN 978-92-64-99206-1, © OECD 2012