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

VIII.1 Halide compounds
155
The measured heat capacity for the β-phase at 298.15 K is (133.3 ± 1.0)
J·K –1·mol –1 . The entropy of β-SnBr 4 at 298.15 K has been obtained by adding the
following parts:
Ttrs
o
S
m
(SnBr 4 , cr, 298.15 K) = C p,m (T 1 )/3 + ( p )
T1
∫
C / d ,m
T T + β H
* / T
Tref
Δ
α m trs+ ∫ ( p )
Ttrs
C / d ,m
T T
where T 1 = 6.66, T trs = 287 and T ref = 298.15 K, see Appendix A entry [1983BER/STE]
S (SnBr 4 , cr, 298.15 K) = (260.0 ± 0.3) J·K –1·mol –1 .
o
m
Figure VIII-8: Heat capacity data for SnBr 4 (cr) as measured by Berezovskii et al.
[1983BER/STE].
160
140
T
α -> β
= 287 K
T fus
= 302.25 K
–1·mol
–1
C° p,m
/J·K
120
100
80
60
40
20
1983BER/STE
α β liq. smoothed data
α β (I) (II) (III) liq. exp. data
0 < T/K < 6.66: C° p,m
= a D
T 3
6.66 < T/K < 287: C° p,m
= a + b·T + c·T 2 + d·T –1
+ e·T –2 + f·T –0.5
0
0 50 100 150 200 250 300 350
T / K
The data selected by this review for SnBr 4 (cr) are:
which yields:
o
C
p,m
(SnBr 4 , cr, 298.15 K) = (133.3 ± 1.0) J·K –1·mol –1 ,
o
S
m
(SnBr 4 , cr, 298.15 K) = (260.0 ± 0.3) J·K –1·mol –1 ,
Δ G (SnBr 4 , cr, 298.15 K) = − (359.50 ± 3.00) kJ·mol –1 .
f
ο
m
CHEMICAL THERMODYNAMICS OF TIN, ISBN 978-92-64-99206-1, © OECD 2012