Based on the vibrational entropy values of table 6, the excess
vibrational entropy at T = 298.15 K was calculated to be 0.22
and 0.44 J mol
1
K
1
for the CuZn15 and CuZn34 samples,
respectively. Applying a symmetric Margules mixing model to
the data, the maximum extent of the excess vibrational entropy
is obtained yielding
D
max
S
exc;calor
m
/(J mol
1
K
1
)=0.5. The excess
vibrational entropies are generated mainly at low temperatures
(below 90 K) and do not change at temperatures above 300 K
(Section 3.2). The excess entropy values from the literature at
573 K [9, as the most recent data compilation] are much more negative
compared to the excess vibrational entropy derived in this
study (figure 3 and table 6). Since the literature excess entropy is
derived from phase equilibrium experiments, it contains both,
the vibrational and the configurational parts of the entropy. The
difference between literature and our calorimetric excess entropy
values must be, therefore, the excess configurational entropy at
T = 573 K resulting in 0.20 and 0.92 J mol
1
K
573
300
0
1
K
1
for CuZn15
and CuZn34, respectively (table 6).