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

8
I Introduction
subjective choice by the reviewers, supported by their scientific and technical
experience in the corresponding area.
The quality of thermodynamic models cannot be better than the quality of the
data on which they are based. The quality aspect includes both the numerical values of
the thermodynamic data used in the model and the “completeness” of the chemical
model used, e.g., the inclusion of all the relevant dissolved chemical species and solid
phases. For the user it is important to note that the selected data set presented in this
review (Chapter III) is certainly not “complete” with respect to all the conceivable
systems and conditions; there are gaps in the information. The gaps are pointed out in
the main text (Chapters V to XI), and this information may be used as a basis for the
assignment of future research priorities. Two examples for rewarding projects in
experimental thermodynamics must suffice.
Thermodynamic data for Sn 6 O 4 (OH) 4 , hydroromarchite, a corrosion product of
elemental tin are lacking. Investigation of the temperature dependent solubility
according to the reaction
1 6 Sn 6 O 4 (OH) 4 (cr) + 2 H + Sn 2+ + 4 3 H 2 O(l)
would lead to the standard Gibbs energy of Sn 6 O 4 (OH) 4 formation, as well as to
provisional values for its standard enthalpy and its entropy.
The standard entropy of hydration according to the reaction
SnCl 2 (cr) + 2 H 2 O SnCl 2·2H 2 O(cr)
ο
with ΔS = − 31 J·K –1·mol –1 m
per mole of water is probably too negative. A reinvestigation
of S m
ο
ο
(SnCl 2·2H 2 O, cr, 298.15 K) and S m
(SnCl 2 , cr, 298.15 K) would
resolve this problem.
CHEMICAL THERMODYNAMICS OF TIN, ISBN 978-92-64-99206-1, © OECD 2012