Thermodynamic characteristics of triphenylantimony bis(acetophenoneoximate)

Article abstract of DOI:10.1134/S0036024411080218

The temperature dependence of heat capacity C _p ^° = f(T) of triphenylantimony bis(acetophenoneoximate) Ph₃Sb(ONCPhMe) ₂ was measured for the first time in an adiabatic vacuum calorimeter in the range of 6.5-370

Full text of DOI:10.1134/S0036024411080218

ISSN 0036ꢀ0244, Russian Journal of Physical Chemistry A, 2011, Vol. 85, No. 8, pp. 1315–1321. © Pleiades Publishing, Ltd., 2011.
Original Russian Text © A.V. Markin, I.A. Letyanina, N.N. Smirnova, V.V. Sharutin, O.V. Molokova, 2011, published in Zhurnal Fizicheskoi Khimii, 2011, Vol. 85, No. 8,
pp. 1427–1434.
CHEMICAL THERMODYNAMICS
AND THERMOCHEMISTRY
Thermodynamic Characteristics of Triphenylantimony
Bis(acetophenoneoximate)
A. V. Markina, I. A. Letyaninaa, N. N. Smirnovaa, V. V. Sharutinb, and O. V. Molokovac
a Lobachevskii State University, Nizhni Novgorod, 603005 Russia
b Blagoveshchensk State Pedagogical University, Blagoveshchensk, 675015 Russia
c Far East Military Institute, Blagoveshchensk, 675021 Russia
eꢀmail: smirnova@ichem.unn.ru
Received June 10, 2010
°
Abstract—The temperature dependence of heat capacity Cp
= f(T) of triphenylantimony bis(acetophenoneꢀ
oximate) Ph3Sb(ONCPhMe)2 was measured for the first time in an adiabatic vacuum calorimeter in the range
of 6.5–370 K and a differential scanning calorimeter in the range of 350–463 K. The temperature, enthalpy,
and entropy of fusion were determined. Treatment of lowꢀtemperature (20 K
performed on the basis of Debye’s theory of the heat capacity of solids and its multifractal model and, as a
consequence, a conclusion was drawn on the type of structure topology. Standard thermodynamic functions
≤ T ≤ 50 K) heat capacity was
°
Cp
for the compound mentioned in the crystalline and liquid states for the range of
entropy of the formation of crystalline Ph3Sb(ONCPhMe)2 was determined at
(
T
),
H
°
(
T
) –
H
°
(0),
S
°
(
T
)
, and
G
°
(
T
) –
H
°
(0) were calculated according to the experimental data obtained
–460 K. The standard
= 298.15 K.
T
T
→ 0
Keywords: thermodynamic properties, triphenylantimony bis(acetophenoneoximate), calorimetric methods.
DOI: 10.1134/S0036024411080218
INTRODUCTION
triphenylantimony Ph3Sb(ONCPhMe)2 (I) in the
range of 7–460 K; determining its thermodynamic
characteristics of fusion; calculating its standard therꢀ
modynamic functions by the obtained experimental
The chemistry of organic complexes of pentavaꢀ
lent antimony has recently attracted considerable
interest due to its unusual structural possibilities,
which vary from individual monomer structures to
supramolecular assemblies. In addition, organic
derivatives of antimony exhibit substantial antiꢀ
bacterial properties and antitumor activity [1]. The
authors of [2–4] synthesized and identified indiꢀ
vidual organic compounds of pentavalent antiꢀ
mony, e.g., Ph4SbONCPh2, Ph3Sb(ONCPh2)2,
°
(T), H°(T)–H°(0), S°(T), and G°(T)–H°(0)
data: Cp
for the sample I in crystalline and liquid states in the
range of –460 K; calculating the standard
entropy of formation of crystalline compound I at
T
→ 0
T
=
298.15 K; and determining fractal dimensionality
and evaluating the type of structure topology.
D
Ph4SbONCHC4H3O,
Ph4SbONCPhMe,
and
EXPERIMENTAL
Ph3Sb(ONCMe2)2. Until recently, there were virtuꢀ
ally no physicochemical characteristics for pentavaꢀ
lent antimony compounds mentioned in the literaꢀ
ture. Some thermodynamic characteristics for oragaꢀ
noantimony compounds were given in [5]. Earlier, we
studied the standard thermodynamic properties of
pentaphenylantimony Ph5Sb [6], tetraphenylantiꢀ
mony benzophenoneoximate Ph4SbONCPh2 [7],
and tetraphenylantimony acetophenoneoximate
Ph4SbONCPhMe [8] in the range of 0 to 350–450 K.
Parameters of the Sample under Study
Sample I was synthesized according to the proceꢀ
dure described in [9]. Aqueous solution of H2O2 was
added to a solution of triphenylantimony and aceꢀ
tophenone oxime in ether. The mixture was kept for
T = 293 K. Colorless crystals, which were filꢀ
tered and dried, were formed by the oxidation addition
reaction.
12 h at
The following values were found by elemental analꢀ
This work is a continuation of comprehensive ysis (%): C 65.07; H 5.04; N 4.56 (for С34Н31SbO2N2
investigations on the standard thermodynamic propꢀ the calculated values were (%): C 65.73; H 4.99;
erties of a number of pentavalent antimony comꢀ N 4.51). Values for the IR spectrum (
, cm–1) were
pounds and is devoted to the calorimetric study of the 1590 (νCN), 1310, 1190, 1160, 1070, 1020, 990, and
,
ν
temperature dependence of the heat capacity for 920 (νNO). The structure of compound was deterꢀ
1315

1316
MARKIN et al.
C23
C24
C21
C45
C25
C44
C43
C46
C22
C26
C4
N2
O2
C35
C3
C42
C41
C34
C32
C33
C36
C31
C15
C13
N1
Sb
C16
C52
C11
C14
C51
C56
O1
C1
C53
C12
C2
C54
C55
Fig. 1. Molecular structure of triphenylantimony bis(acetophenoneoximate).
mined by Xꢀray analysis. The corresponding data are sured using an iron–rhodium resistance thermometer
given in [9]. The molecular structure of compound is
shown in Fig. 1. According to the data from our analꢀ
yses, determined within the experimental error of
measurement, the content of the main substance in
the sample under study was not less than 99.5 mol %.
(R ≅ 100 Ω) calibrated according to ITSꢀ90. The temꢀ
perature difference between the ampoule and adiaꢀ
batic shell was controlled using a fourꢀsoldered copꢀ
per—iron–chromel thermocouple. The reliability of
°
the calorimeter was verified by measuring Cp of stanꢀ
The thermal stability of I was studied using
TG209F1 thermal microscales (Netzsch Geratebau,
Germany). We determined that a considerable loss in
weight related to the destruction of the sample is
dard samples of pure copper, standard corund, and Kꢀ3
brand benzoic acid, and the temperatures and enthalꢀ
pies of fusion for
nꢀheptane. It was determined that the
apparatus and measuring technique allowed us to
observed at
T = 460 K; further, with an increase in
°
obtain values Cp of the substances with an error of
temperature of 10 K, the loss of weight increases
from 2% and takes the value of 10% at 500 K. In an
inert medium, the sample of triphenylantimony
bis(acetophenoneoximate) is thus thermally stable
up to 460 K.
2% up to 15 K; 0.5% in the range of 15–40 K; and
0.2% in the range of 40–370 K; and to measure the
temperatures of phase transitions with an error of
0.01 K in accordance with ITSꢀ90.
A DSC204F1 Phoenix differential scanning caloꢀ
rimeter (Netzsch Geratebau, Germany) was used to
measure the heat capacity of sample I in the range of
350–460 K. Both the design of the calorimeter and the
procedure were described, e.g., in [12, 13]. The reliꢀ
ability of the calorimeter was verified by standard calꢀ
ibrating experiments on measuroffing the thermodyꢀ
Apparatus and Measuring Technique
We used a fully automatic BKTꢀ3 adiabatic vacuum
calorimeter (AOZT Termis, Russia) to study the temꢀ
°
perature dependence of heat capacity Cp
= f(T) in the
range of 6–370 K. Liquid helium and nitrogen were
used as refrigerants. An ampoule with the substance
was filled to a pressure of 40 kPa at room temperature
by dry helium as the thermal exchange gas. Both the
design of the calorimeter and the procedure were analꢀ
ogous to those described in [10, 11]. The calorimetric
ampoule was a thinꢀwalled cylinder of titanium with a
namic characteristics of fusion for nꢀheptane, merꢀ
cury, indium, tin, lead, bismuth, and zinc. It was
determined that the apparatus and measuring techꢀ
nique allowed us to measure the temperatures of phase
transitions with an error of 0.5 K, and the enthalpies
of transitions with an error of 1%. The heat capacity
volume of 1.5
×
10–6 m3. The temperature was meaꢀ was determined by the ratio method, with Corund
RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A
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1317
THERMODYNAMIC CHARACTERISTICS
used as a standard reference sample. The technique for oms; corresponding coefficients were calculated by
the least squares method with the use of special proꢀ
grams.
°
determining Cp according to the data of DSC meaꢀ
surements is described in detail in [12] and the
Netzsch Proteus Software. Individual values Cp, sp were
determined according to Eq. (1) at different temperaꢀ
tures:
The rootꢀmeanꢀsquare deviation of the experiꢀ
°
°
mental points of Cp from the corresponding smoothꢀ
°
ened curve Cp
= f(T) did not exceed 0.5% in the
range of 20–90 K; 0.2%, in the range of 112–250 K;
0.1% in the range of 240–370 K; and 0.7%, in the
range of 450–463 K. The molar weight of the object
under study was calculated from the IUPAC table of
atomic weights [14].
mstd DSCs(T) − DSCbl(T)
ms DSCstd(T) − DSCbl(T)
ꢀ
ꢀ
(1)
Cp,s
=
Cp,std,
°
where Cp, s is the specific heat capacity of a sample at
°
temperature
T;
Cp, std is the specific heat capacity of the
Experimental values of the heat capacity of I and
standard (corundum) at temperature
mass of the standard; ms is the mass of the sample
under study; DSCs is the value of the DSC signal at
T;
mstd is the
°
the smoothed curve Cp = f(T) are given in Fig. 2. In the
studied temperature range, triphenylantimony
bis(acetophenoneoximate) was in the crystalline (AB
section, Fig. 2) and liquid (CD section, Fig. 2) states.
The heat capacity of I in the crystalline state smoothly
increases with a rise in temperature. The drastic
increase in heat capacity and subsequent break in the
curve were determined by the fusion of the crystals of
substance.
In addition to fusion, a reproducible anomaly is
observed on the curve of temperature dependence of
the heat capacity of I (FGH section, Fig. 2) in the
range of 85–110 K. The temperature corresponding to
the maximum value of the apparent heat capacity in
the range of transformation was 99.5 0.5 K. Accordꢀ
ing to the McCullough classification [15, 16], this
temperature
is the value of the DSC signal at temperature
the curve of reference sample ( V); and DSCbl is the
value of the DSC signal at temperature from the
baseline ( V).
T
from the curve of sample (
μ
V); DSCstd
T
from
μ
T
μ
Three different measurements were performed to
calculate the heat capacity: one for the baseline, one
for the standard (corundum), and one for the sample
under study. In these measurements, the following
parameters remained identical: the flow of argon, the
rate of argon flow, the starting temperature, the heatꢀ
ing rate and scanning rate, the mass of the crucible and
cap, and the position of the crucible on the sensor.
During measurement of the heat capacity, the sample
was kept at a constant temperature (293 K) for 30 min
in the argon flow; heating was then performed at a
constant rate (1 K/min) up to 460 K; and the measureꢀ
ments were terminated with subsequent cooling of the
system to room temperature. Measurements for the
baseline and standard were performed in the same
manner.
transition could be related to a
state. Its enthalpy Δtr = 86.84 0.17 J/mol and
entropy Δtr = 0.8827 0.0018 J/(mol K) were calꢀ
λ transition in the solid
H°
S°
°
culated using the area between the curves Cp = f(T)
°
and Cp = f(lnT) with the λ transition and correspondꢀ
ing interpolation curves. The calorimetric data were
insufficient for determining the nature of this transiꢀ
tion without a number of additional structural investiꢀ
gations.
°
Note that the error determining Cp by the above
method was no worse than 2%. Measurements of
thermophysical characteristics were performed with
an ampoule of substance at an average heating rate of
1 K/min in an atmosphere of argon.
It was interesting to obtain the value of fractal
dimensionality
18] by the experimental data on lowꢀtemperature heat
capacity. Fractal dimensionality is an exponent of
D for the substance under study [17,
D
temperature in the main equation of the fractal model
of treatment for lowꢀtemperature heat capacity. Values
RESULTS AND DISCUSSION
D
allow us to draw some conclusions on the type of the
The heat capacity of I was studied in the temperature
range of 6.5–370 K (Table 1) by AVC, and in the range
of 350–460 K, by DSC. Subsequent shots of sample
structure topology of solids, and they can be obtained
from the graph of lnCv versus lnT. This follows from
the following equation:
were placed in calorimetric ampoules: 0.5235
×
10–3 kg
in AVC, and 0.023
×
10–3 kg in DSC. In AVC,
С
v = 3
where is the Boltzmann constant,
atoms in a molecule, + 1) is the gamma function,
+ 1) is the Riman function, and Θmax is the
intrinsic temperature. For a particular solid,
1)kN + 1) is a constant
+ 1)(1/Θmax)D =
value. Equation (2) can then be written as follows:
ln v = ln ln
D(D
+ 1)kNγ(D
+ 1)
ξ(D
+ 1)(
T/
Θmax)D, (2)
°
213 experimental values of Cp were obtained in two
k
N
is the number of
series, reflecting the continuity of the experiment. The
heat capacity of the compound under study everyꢀ
where assumed value of 45–65% of the total heat
capacity of the calorimetric ampoule with the subꢀ
γ(D
ξ(
D
ξ
3D(D +
γ(D
ξ(D
A
°
stance. The experimental points of Cp were smoothed
C
A
+
D
T.
(3)
by means of exponential and semilogarithmic polynꢀ
RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A
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MARKIN et al.
Table 1. Experimental values of the heat capacity (J/(mol K)) of triphenylantimony bis(acetophenoneoximate)
Ph3Sb(ONCPhMe)2 (
M
= 621.38 g/mol)
°
Cp
°
Cp
°
Cp
°
Cp
°
Cp
°
Cp
T
, K
T, K
T, K
T, K
T, K
T
, K
Series 1
31.03
32.05
33.08
34.13
35.20
36.30
37.40
38.51
39.64
40.78
41.94
43.10
44.00
45.47
46.67
47.79
49.08
50.30
51.53
52.77
54.01
55.26
56.52
57.78
59.06
60.35
61.69
62.89
64.18
65.40
66.76
68.06
69.36
70.66
71.95
73.24
88.20
92.00
96.00
99.83
103.7
107.5
110.8
114.3
118.0
121.8
125.6
129.5
132.2
137.2
141.3
144.5
148.0
152.0
154.9
158.4
161.8
165.3
168.7
172.0
175.3
178.9
182.5
185.8
189.3
193.0
196.5
200.0
203.2
206.9
210.4
214.1
74.53
75.86
77.11
78.42
79.72
81.03
82.26
83.65
84.82
86.26
87.58
88.89
90.20
91.52
217.3
220.8
224.2
227.2
230.4
234.1
237.0
240.5
244.0
248.0
251.3
255.2
258.4
262.0
122.88
124.96
127.05
129.12
131.30
133.24
135.31
137.38
139.45
141.51
143.57
145.63
147.68
150.20
152.60
155.38
158.46
161.53
164.59
167.65
170.64
173.68
176.71
179.73
182.74
185.73
188.71
191.69
194.66
197.61
200.57
203.51
206.43
209.30
212.25
215.14
317.0
320.7
324.3
328.3
332.3
336.4
340.0
343.6
347.5
351.5
355.5
358.9
362.8
367.4
371.9
377.5
383.1
388.6
394.4
400.4
406.4
412.6
418.9
424.5
430.6
437.0
442.9
448.3
453.9
459.6
465.3
470.8
476.2
481.1
487.4
492.5
217.91
220.78
223.63
226.45
229.26
232.07
234.85
237.63
240.38
243.12
245.84
248.54
251.21
253.87
256.50
259.08
261.42
263.99
266.50
269.02
271.51
273.98
276.43
278.83
281.25
283.61
285.95
288.32
290.66
292.98
295.29
297.58
300.00
301.69
303.91
306.11
497.9
503.9
509.7
516.0
522.6
528.1
534.3
539.3
545.3
551.0
556.5
562.4
568.3
574.0
580.0
585.2
590.8
596.4
602.2
607.6
613.3
618.9
624.5
630.0
635.7
640.8
646.3
651.2
656.5
661.5
666.4
671.4
676.3
679.6
683.9
688.8
308.29
310.50
312.64
314.81
316.97
319.10
321.21
323.30
325.33
327.38
329.31
331.32
332.65
334.64
336.59
338.53
340.38
342.28
344.15
345.70
347.75
349.55
351.34
353.09
354.83
356.54
358.23
359.81
360.71
362.35
308.29
363.95
365.54
367.11
368.64
370.35
693.5
698.1
701.7
705.7
710.4
714.4
718.5
722.5
726.5
730.0
734.4
738.7
741.3
745.2
749.5
753.6
757.6
762.2
766.5
769.8
774.7
779.7
783.9
787.9
792.3
796.2
799.8
803.4
805.8
809.1
693.5
812.7
816.3
820.0
823.7
827.7
6.52
7.23
4.05
5.32
6.07
7.15
8.09
9.09
9.93
7.62
8.11
8.55
8.97
9.39
9.85
11.2
10.27
10.68
11.07
11.45
11.84
12.40
13.14
13.88
14.61
15.33
16.13
16.85
17.58
18.32
19.08
19.84
20.80
21.67
22.54
23.42
24.31
25.29
26.14
27.09
28.05
29.03
30.02
12.3
13.8
14.9
16.2
17.5
19.1
Series 2
21.5
79.29
81.31
229.4
235.0
240.8
246.4
252.0
257.2
263.1
269.0
275.0
279.6
283.8
287.2
290.2
290.7
292.1
295.3
298.3
302.3
305.7
309.6
313.0
24.0
26.7
83.37
29.10
32.13
34.90
38.00
41.00
44.20
47.10
50.60
53.60
56.70
59.67
63.00
66.62
69.85
73.45
77.06
80.90
84.31
85.44
87.50
89.56
91.63
93.69
95.76
97.96
100.00
102.06
104.14
106.21
108.29
110.38
112.46
114.54
116.63
118.72
120.60
°
Θmax = 194.8 K. These values were determined with an
error of 0.9%. According to the Tarasov theory of the
The experimental values Cp can be considered as
Cv without considerable error for
corresponding experimental data on heat capacity for
the range of 20–50 K and Eq. (3), the value can then
be obtained. It was discovered that for I, the fractal
dimensionality was 1.6 and intrinsic temperature In Table 2, the corresponding values are given for I and
T < 50 K. Using the
heat capacity of solids [19, 20],
the chain structure; = 2, to the layer structure; and
= 3, to the spatial structure. Our obtained value
indicates a layerꢀchain topology for the structure of I.
D = 1 corresponds to
D
D
D
D
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THERMODYNAMIC CHARACTERISTICS
Cp°, J/(K mol)
C
C
'
Cp°, J/(K mol)
1600
1200
800
300
250
200
G
H
F
E
D
B
50
100
150
T, K
50
25
400
A
I
A
0
10
40
500
T, K
0
100
200
300
400
T, K
Fig. 2. Temperature dependence of the heat capacity of triphenylantimony bis(acetophenoneoximate): AB is crystal, BCC
'D is
the apparent heat capacity in the fusion range, DE is liquid, FGH is the apparent heat capacity in the range of the transition,
λ
°
and IA represents the extrapolation values of Cp according to Eq. (7).
the compounds we studied earlier: pentaphenylantiꢀ 434.5
0.5 K. Fusion enthalpy ΔfusH° = 42.0
mony Ph5Sb [6], tetraphenylantimony benzopheꢀ
noneoximate Ph4SbONCPh2 [7], and tetraphenylantiꢀ experiments, also in accordance with the software’s
0.6 kJ/mol was determined as the average from three
standard procedure. Fusion entropy Δfus ° = 96.7
1.4 J/(K mol) was determined using the following
equation:
S
mony acetophenoneoximate Ph4SbONCPhMe [8].
The values of the intrinsic Debye temperatures Θmax
calculated for the same degrees of freedom and temꢀ
perature range allow us to draw some conclusions on
the relative rigidity of the structures of solids.
ꢀ
ꢀ
ꢀ
(4)
ΔfusS = ΔfusH /Tfus.
According to our results, Θmax(Ph4SbONCPh2)
≈
Θmax(Ph3Sb(ONCPhMe)2) < Θmax(Ph4SbONCPhMe) <
Θmax(Ph5Sb). The rigidity of the crystalline structures
of the compared compounds increases in the same
order. This tendency should apparently hold at higher
temperatures.
Table 2. Fractal dimensionalities
tures Θmax
D and intrinsic temperaꢀ
Substance
T
, K
D
Θmax, K
δ, %
Ph3Sb(ONCPhMe)2
7
20
6
−11
−50
−11
−50
−11
−50
−11
−50
3.0
1.6
3.0
1.3
3.0
1.6
3.0
1.6
63.7
194.8
60.6
1.4
0.9
1.7
1.0
0.4
1.0
1.6
0.7
Ph5Sb [6]
Thermodynamic Characteristics of Fusion
20
6
246.7
76.1
Temperature range of fusion from 423 to 453 K was
determined graphically according to the DSC curves.
The temperature corresponding to the onset of transiꢀ
tion was, in accordance with the Netzsch Proteus
Ph4SbONCPh2 [7]
Ph4SbONCPhMe [8]
20
6
195.3
64.5
°
Software, considered the fusion temperature: Tfus
=
20
210.1
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MARKIN et al.
Table 3. Standard thermodynamic functions of triphenylantimony bis(acetophenoneoximate) Ph3Sb(ONCPhMe)2 (
621.38 g/mol)
M =
°
Cp
Т
, K
(Т
), J/(K mol)
H
°
(
T
) –
H°(0), kJ/mol
S°(
T), J/(K mol)
−[G°(T) – H°(0)], kJ/mol
Crystalline state
0.00230
0.0332
0.131
0.3174
0.5994
0.9747
1.443
1.998
2.637
3.353
4.998
5
10
15
20
25
30
35
40
45
50
60
70
80
1.87
11.6
27.9
0.625
4.50
12.2
0.000781
0.0118
0.0521
0.1385
0.2834
0.4935
0.7739
1.128
1.556
2.060
3.292
4.822
47.55
65.55
84.51
102.5
119.6
135.7
150.6
178.2
205.1
231.5
258.4
283.8
294.6
311.5
330.3
348.5
366.8
385.9
405.6
425.4
444.8
463.9
483.0
502.6
523.3
544.8
565.7
587.4
609.9
632.7
655.1
672.5
676.3
696.5
716.0
735.9
757.1
780.1
804.1
828
22.80
35.31
48.94
63.33
78.15
93.18
108.3
138.2
167.7
196.8
225.6
254.2
281.8
308.2
333.8
359.0
383.7
407.9
431.9
455.7
479.2
502.5
525.6
548.5
571.3
594.0
616.7
639.3
661.9
684.5
707.1
725.5
729.6
752.1
774.6
796.9
819.2
841.5
863.8
886
6.915
9.098
6.644
8.756
90
11.55
14.27
17.16
20.19
23.40
26.80
30.37
34.14
38.09
42.25
46.60
51.14
55.88
60.80
65.93
71.27
76.83
82.59
88.58
94.79
101.2
106.6
107.9
114.8
121.8
129.1
136.5
144.2
152.1
160
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
270
280
290
298.15
300
310
320
330
340
350
360
370
380
390
400
410
420
430
434.5
11.16
13.84
16.79
20.00
23.46
27.18
31.13
35.33
39.77
44.45
49.35
54.49
59.87
65.46
71.29
77.34
83.62
90.13
96.86
103.8
109.7
111.0
118.4
126.0
133.9
142.0
150.3
158.8
168
851
874
898
921
944
968
978
169
177
186
195
205
214
219
908
931
953
976
998
1021
1031
177
186
195
205
215
225
229
Liquid state
434.5
440
450
1094
1088
1078
1068
261
267
277
288
1128
1141
1166
1189
229
236
247
259
460
RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A
Vol. 85
No. 8 2011

1321
THERMODYNAMIC CHARACTERISTICS
REFERENCES
ꢀ
ꢀ
The increase in heat capacity
=
ΔCp (Tfus)
1. A. Gupta, R. K. Sharma, R. Bohra, et al., Polyhedron
116 J/(K mol) of the substance under study upon
fusion was found graphically by extrapolating the norꢀ
21, 2387 (2002).
2. V. V. Sharutin, O. K. Sharutina, O. V. Molokova, et al.,
Zh. Obshch. Khim. 71, 1317 (2001) [Russ. J. Gen.
Chem. 71, 1243 (2001)].
3. V. V. Sharutin, O. K. Sharutina, O. V. Molokova, et al.,
Zh. Obshch. Khim. 70, 1990 (2000) [Russ. J. Gen.
Chem. 70, 1872 (2000)].
4. V. A. Dodonov, A. V. Gushchin, D. A. Gor’kaev, et al.,
Izv. Akad. Nauk, Ser. Khim., No. 6, 965 (2002).
5. I. B. Rabinovich, V. P. Nistratov, V. I. Tel’noi, et al.,
Thermodynamics of MetalꢀOrganic Compounds (Nizheꢀ
gor. Gos. Univ., Nizh. Novgorod, 1996) [in Russian].
°
mal path of Cp versus
T
to the temperature of phase
fus. Using the thermodynamic characterisꢀ
tics of fusion for , we calculated the first
(K–1) and
the second
(K–1) cryoscopic constants according to
the following equations:
°
T
transition
I
A
B
2
ꢀ
ꢀ
(5)
(6)
A = ΔfusH /[R(Tfus) ] = 0.0268 0.0003,
o
ꢀ
ΔCp (Tfus)
−1
1
2
ꢀ
B = (Tfus)
−
= 0.00092 0.00003,
ꢀ
6. N. N. Smirnova, I. A. Letyanina, V. N. Larina, et al.,
Δfus
H
J. Chem. Thermodyn. 41, 46 (2009).
where
R
is a universal gas constant.
7. N. N. Smirnova, I. A. Letyanina, A. V. Markin, et al.,
Zh. Obshch. Khim. 79, 553 (2009) [Russ. J. Gen.
Chem. 79, 717 (2009)].
Standard Thermodynamic Functions
8. I. A. Letyanina, N. N. Smirnova, A. V. Markin, et al.,
J. Therm. Anal. Cal. 103, 355 (2011).
To calculate the standard thermodynamic funcꢀ
tions (Table 3), the temperature dependence of the
heat capacity of I was extrapolated from 6.5 to 0 K by
the Debye function of the heat capacity of solids:
9. V. V. Sharutin, O. K. Sharutina, O. V. Molokova, et al.,
Koord. Khim. 28, 497 (2002) [Russ. J. Coord. Chem.
28, 464 (2002)].
10. R. M. Varushchenko, A. I. Druzhinina, and E. L. Sorꢀ
kin, J. Chem. Thermodyn. 29, 623 (1997).
11. V. M. Malyshev, G. A. Mil’ner, E. L. Sorkin, et al., Prib.
°
Cp
=
nD(ΘD/Т),
(7)
Tekh. Eksp. 6, 195 (1985).
where D is the Debye function of heat capacity,
is the number of degrees of freedom, and ΘD = 63.7 K
is the Debye intrinsic temperature. Equation (7)
describes the experimental values of heat capacity Cp
n
= 6
12. G. W. H. Hohne, W. F. Hemminger, and H. F. Flamꢀ
mersheim, Differential Scanning Calorimetry (Springer,
Berlin; Heidelberg, 2003).
°
13. V. A. Drebushchak, J. Therm. Anal. Cal. 79, 213
(2005).
with these parameters in the range of 6.5–12 K with an
error of 1.4%. We accepted that in the range of 0–6.5 K, 14. Atomic Weights of the Elements 1993, IUPAC Commisꢀ
sion on Atomic Weights and Isotopic Abundance’s
J. Phys. Chem. Ref. Data 24, 1561 (1995).
,
Eq. (7) reproduces the heat capacity values with the
same degree of error.
15. Physics and Chemistry of The Organic Solid State, Ed. by
D. Fox, M. Labes, and A. Weissberger (Interscience,
New York London, 1965; Mir, Moscow, 1968).
CONCLUSIONS
16. D. Stull, E. Westrum, and G. Sinke, Chemical Thermoꢀ
dynamics of Organic Compounds (Wiley, New York,
1969; Mir, Moscow, 1971).
The procedure for calculating enthalpy
(0), entropy , and Gibbs function
H
°
(
(
T
) –
H°
S°
(T)
G°
T) –
H
°
(0) was described in detail, e.g., in [21, 22]. The
17. T. S. Yakubov, Dokl. Akad. Nauk SSSR 310, 145
error of the calculated function values assumed a value
of 2% at < 15 K, 0.6% in the range of 15 to 40 K,
and 2.5% in the range of 370 to 463 K.
(1990).
Т
18. V. B. Lazarev, A. D. Izotov, K. S. Gavrichev, et al.,
Thermochim. Acta 269–270, 109 (1995).
19. V. V. Tarasov, Zh. Fiz. Khim. 24, 111 (1950).
Using the value of absolute entropy of I (Table 3)
and simple substances (carbon [23], hydrogen [24],
oxygen [25], nitrogen [25], and antimony [25]), we
calculated the standard entropy of formation of crystal I
20. V. V. Tarasov and G. A. Yunitskii, Zh. Fiz. Khim. 39
,
2077 (1965).
21. B. V. Lebedev, Thermochim. Acta 297, 143 (1997).
ΔfS° = –1935.5 1.9 J/(K mol) at T = 298.15 K. The
obtained value corresponds to the following equation:
22. J. P. McCullough and D. W. Scott, Calorimetry of Nonꢀ
Reacting Systems (Butterworth, London, 1968).
23. Codata Key Values for Thermodynamics, Ed. by J. D. Cox,
D. D. Wagman, and V. A. Medvedev (New York, 1984).
24. M. W. Chase, Jr., J. Phys. Chem. Ref. Data, Monoꢀ
34С(gr) + 15.5H2(g) + Sb(cr) + O2(g) + N2(g)
(8)
→ Ph3Sb(ONCPhMe)2(cr),
graph 9, 1951 (1998).
where the physical states of reagents are indicated in
parentheses: gr is graphite, g is gas, and cr is crystalꢀ
line.
25. Thermal Constants of Materials. Handbook, Ed. by
V. P. Glushko (VINITI, Moscow, 1965–1981), Nos. 1–
10 [in Russian].
RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A
Vol. 85
No. 8 2011