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

124
VII Tin oxygen and hydrogen compounds and complexes
Figure VII-9: Solubility of SnO(cr) in 1.0515 m NaClO 4 solutions (: experimental
data of [1966MES/IRA]; solid line: linear fit of the experimental data fixed slope
ο
– 2.00; dash dotted line: ΔfGm(SnO, cr, 298.15 K) = − 253.116 kJ·mol –1
ο
([1941GAR/HEI], [1942GOR/LEI]); dotted line: Δf G m (SnO, cr, 298.15 K) =
− 253.938 kJ·mol –1 * ο
ο
(Δ( log 10
K
s0
) = 0.1); dash dot line: Δ (SnO, cr, 298.15 K) =
− 255.080 kJ·mol –1 fGm
(Δ( log K ) = − 0.1)).
* ο
10 s0
-1.0
-1.5
log 10
(m Sn
2+/mol·kg –1 )
-2.0
-2.5
-3.0
-3.5
Δ f
G° m
(SnO, cr, 298.15 K)/kJ·mol –1
-253.938 (Δlog 10
*K' s0
= + 0.1)
-254.509 [66MES/IRA]
-255.080 (Δlog 10 * K' s0
= - 0.1)
-253.116 ([41GAR/HEI], [42GOR/LEI],
log 10
*K' s0
= (2.64 ± 0.24)
-4.0
1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0
pH = – log 10
a H
+
Unfortunately neither Mesmer and Irani [1966MES/IRA], nor Garrett and
Heiks [1941GAR/HEI], nor Gorman and Leighton [1942GOR/LEI] characterised their
solid phases by taking the respective X-ray powder diffraction patterns.
Blue-black tetragonal tin(II) oxide, which is the stable form at 25 °C
[1961DON/MOS2], is easily formed if an excess of sodium hydroxide is added to a
solution of tin(II) chloride [1967KWE/VRO]. As other tin(II) oxide or tin(II) hydroxide
phases are less stable and more soluble than black tetragonal SnO, Mesmer and Irani
[1966MES/IRA] very probably investigated this phase.
ο
The value of S m (O 2 , g, 298.15 K) can be taken from the auxiliary data in
ο
–1
Table IV-1. This review selected Sm (SnO, cr, 298.15 K) = (57.18 ± 0.22) J·K
–1·mol
ο
and m (Sn, white, 298.15 K) = (51.18 ± 0.08) J·K–1·mol –1 ο
S
, thus Δ f S m for Reaction
ο
(VII.22) can be calculated and ΔfGm(SnO, tetragonal, 298.15 K) can be obtained from
ο
measured Δ H or vice versa
f
m
CHEMICAL THERMODYNAMICS OF TIN, ISBN 978-92-64-99206-1, © OECD 2012