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

V.1 Tin crystal
87
For white tin, the enthalpy difference ( H m (Sn, β, 298.15 K) − H m (Sn, β,
ο
0 K)), as derived from the selected equation for C p ,m (Sn, β, T ) ( Table V-6), the
original evaluators [1991GUR/VEY] assigned an uncertainty of ± 0.08 J·K –1·mol –1 .
ο
They similarly assigned an uncertainty in C (Sn, β, 298.15 K) of 0.08 J·K –1·mol –1 .
p,m
From Table V-7, it may be concluded that a low, rather than a high, value of
ο
S m (Sn, β, 298.15 K) is preferable. The present evaluation therefore selects that of
[1991GUR/VEY], which corresponds to the value chosen by CODATA
[1989COX/WAG].
The selected data for the heat capacity of white tin [1991GUR/VEY] are for
298 < T/K < 505 generated by the equation:
ο 505K
C p ,m 298K
[ ]
(Sn, β, T )/J·K –1·mol –1 = 34.297 − 2.9957 × 10 –2 T/K
+ 5.0794 × 10 –5 (T/K) 2 − 2.461 × 10 5 (T/K) –2
ο
–1
C
p,m
(Sn, β, 298.15 K) = (27.11 ± 0.08) J·K
–1·mol
and for the standard entropy the value
ο
–1
S m (Sn, β, 298.15 K) = (51.18 ± 0.08) J·K
–1·mol
has been selected.
CHEMICAL THERMODYNAMICS OF TIN, ISBN 978-92-64-99206-1, © OECD 2012