Intercalation and formation of complexes in the system of lead(II) iodide-ammonia

Article abstract of DOI:10.1016/j.jssc.2003.09.028

Interaction between lead(II) iodide and ammonia was studied with the help of an X-ray in situ analysis, DTA-TG analysis, DSC measurements and IR spectroscopy. A two-stage mechanism of the reaction was defined. At the first stage of the reaction two phases with trigonal symmetry and a phase with monoclinic symmetry are developed. At the second stage of the reaction the structure changes lead to formation of a compound with orthorhombic symmetry. The results were discussed along with the data of thermal analysis and IR spectroscopy. The value of enthalpy of formation for the compound PbI ₂(NH₃)₄ was determined.

Full text of DOI:10.1016/j.jssc.2003.09.028

ARTICLE IN PRESS
Journal of Solid State Chemistry 177 (2004) 909–915
Intercalation and formation of complexes in the system
of lead(II) iodide–ammonia
G.I. Gurinaa and K.V. Savchenkob,ꢀ
a Department of Polymeric Composite Materials, National Technical University ‘‘KhPI,’’ Kharkov 61002, Ukraine
b Institute for Low Temperature Physics and Engineering, The National Academy of Sciences of Ukraine, Kharkov 61103, Ukraine
Received 4 July 2003; received in revised form 6 September 2003; accepted 24 September 2003
Abstract
Interaction between lead(II) iodide and ammonia was studied with the help of an X-ray in situ analysis, DTA-TG analysis, DSC
measurements and IR spectroscopy. A two-stage mechanism of the reaction was defined. At the first stage of the reaction two phases
with trigonal symmetry and a phase with monoclinic symmetry are developed. At the second stage of the reaction the structure
changes lead to formation of a compound with orthorhombic symmetry. The results were discussed along with the data of thermal
analysis and IR spectroscopy. The value of enthalpy of formation for the compound PbI2(NH3)4 was determined.
r 2003 Elsevier Inc. All rights reserved.
Keywords: Lead(II) iodide; Ammonia; Intercalation; Complex
1. Introduction
determined [25,26]. Kinetics of the changes in diffraction
patterns on incorporation of hexahydropyridine mole-
cules into textured films of PbI2 were studied [14].
In this paper, we speak about our study of consequent
changes in crystal structure of lead iodide and in
properties of intercalate during incorporating NH3
molecules. Methods of an X-ray structure analysis in
situ, DTA-TG analysis, differential scanning calorime-
try (DSC) and infrared spectroscopy were used.
Intercalation of various electron-donating molecules
into interlayer of PbI2 crystals having a layered structure
has been studied widely in recent decades [1–16]. In
particular, thermodynamics of forming intercalated
compounds of PbI2 [9,17,18], photochemical reactions
of intercalated compounds and photolysis of PbI2
sensitized by molecules of intercalates [17,19–21], as
well as properties of intercalated phases of PbI2
[8,18,22,23] were studied. There was shown the possibi-
lity of using PbI2 for quantitative determination of
amines in non-reducing media [19]. In this connection a
study of PbI2–intercalate systems, in which formation of
several intercalated phases occurs, is of special interest.
PbI2–2-aminoethanol [8,20], PbI2–pyridine [1,9,22],
PbI2–hexahydropyridine [1,14] and PbI2–ammonia
[12,20,21,23] are examples of such systems.
2. Experimental
The purity of PbI2 powder was checked by an X-ray
analysis and IR spectroscopy. The purity of gaseous
NH3 was checked by the IR spectroscopy method. An
X-ray study was carried out with the help of two powder
X-ray diffractometers using CuKa radiation. The lattice
parameters and their standard deviations were calcu-
lated using a dichotomy method [27] after least-squares
refinement of peak positions. The profiles of the
diffraction lines were fitted with a Pseudo-Voigt func-
tion. To indexthe powder diffraction patterns a
DICVOL93 program (D. Louer and A. Boultif), to
calculate the theoretical X-ray powder diffraction
patterns a LAZYPULVERIX program (K. Yvon) and
An X-ray analysis in situ was carried out for the
system of PbI2–NH3 [24–26] and PbI2–C5H11N [14].
Changes of the unit-cell parameters of PbI2 crystal
matrix [24] and development of a metastable phase were
ꢀCorresponding author. B. Verkin Institute for Low Temperature
Physics and Engineering, National Academy of Sciences, 47 Lenin
Ave., UA-61103 Kharkov, Ukraine. Fax: +38-05-72-64-96-45.
E-mail address: konstantin@kharkov.com (K.V. Savchenko).
0022-4596/$ - see front matter r 2003 Elsevier Inc. All rights reserved.
doi:10.1016/j.jssc.2003.09.028

ARTICLE IN PRESS
G.I. Gurina, K.V. Savchenko / Journal of Solid State Chemistry 177 (2004) 909–915
910
to fit the profiles of diffraction lines a DIFFRAC/AT
program (SOCABIM) there were used.
%
A trigonal system and a P3ml space group for a pure
development of the double peak at 2Yꢂ1 ¼ 11:60ꢂ and
2Yꢂ2 ¼ 11:81ꢂ and an increase in peak intensity of the
phase III lead to this conclusion.
PbI2 powder with the hexagonal unit-cell parameters of
a ¼ 4:5569ð4Þ A and c ¼ 6:9803ð12Þ A were revealed.
The lattice parameters were in a good concordance with
the data of the work [28] and corresponded to 2H
polytype of PbI2. After deammoniation a restoration of
the PbI2 structure was observed.
The appearance of diffraction lines at lower angles is
induced by the enlarged size of the unit cell in c-axis,
which is a typical manifestation of incorporation of
guest molecules into a host matrix [2,6]. Theoretical
diffraction patterns for PbI2 with the values c1 ¼ 7:49 A
ꢂ
ꢂ
%
(for 2Y1) and c2 ¼ 7:62 A (for 2Y2) in P3ml space group
were calculated and compared with the diffraction
patterns obtained experimentally. A new parameter of
the unit cell a1 was selected using the most intensive lines
from the (001), (011), (102), (012), (110), (103) and (201)
planes. The value a1 was found to be the same for the
both values c1 and c2; which was equal to 4.92 A. It
exceeded the initial value for PbI2 lattice by 0.38 A.
Thus, at the first stage of the reaction the two kinds of
the unit cells with enlarged hexagonal parameters
a1 ¼ 4:92 A, c1 ¼ 7:62 A and a1 ¼ 4:92 A, c2 ¼ 7:49 A
were formed—phases I and II, respectively. The
enlarged size of the unit cell in a-axis by 0:220:4 A
together with the enlarged size in c-axis by 5:8214:1 A
was also found [14] during hydrazine-intercalation of
thin evaporated films and powdered single crystals of
PbI2 at a pressure of about 20 Torr.
To perform an X-ray analysis in situ in course of
interaction between PbI2 and NH3 the sample of PbI2
powder was placed into a special vacuum chamber
equipped with a valve, an inlet for gaseous ammonia
supply and a gas-pressure-measuring system. At a lower
temperature a decrease in the reaction rate occurs which
made it possible to record the diffraction patterns at the
intermediate stages of the reaction. Our X-ray diffrac-
tion experiments were performed at a temperature of
285 K. The previously evacuated chamber was filled with
gaseous ammonia up to a pressure of about 760 Torr.
Calorimetric measurements were carried out by the
DSC with the help of a diathermal-shell calorimeter. A
sample was prepared in a small glass ampoule. The
previously evacuated ampoule with PbI2 powder was
filled with gaseous ammonia up to a pressure of 760 Torr
and maintained under that condition for 96 h. To avoid
decomposition, the ampoule was cooled to the liquid
nitrogen temperature and was immediately sealed. The
exposure time of a PbI2 sample in ammonia medium was
chosen to be 96 h, since at the longer exposure times no
changes in the diffraction patterns were observed. The
heating rate of the sample was equal to 5 K minꢁ1 during
the DSC measurements.
Table 1 shows the X-ray diffraction data with
assigned Miller indices for the phase III. Stoichiometry
of the phases was determined by DTA–TG analysis and
corresponded to the compound of PbI2(NH3)2.47. The
lattice parameters for the phase III were calculated:
a ¼ 10:23ꢂ8ð11Þ A, b ¼ 12:061ð8Þ A, c ¼ 9:587ð8Þ A, b ¼
107:73ð7Þ and V ¼ 1127:54 A3. The lattice symmetry of
the phase III was found to be monoclinic.
Besides, the methods of differential thermal analysis
(DTA) and thermogravimetric analysis (TG) in argon
atmosphere employing a Paulic–Paulic–Erday thermo-
analyser were used. The heating rate was equal to
5 K minꢁ1. A double-beam ‘‘Specord IR-75’’ spectro-
photometer was used in an infrared study. PbI2 powder
of was put on a KBr plate. Then the sample was placed
into a gas chamber equipped with an inlet for gaseous
ammonia supply and a gas-pressure-measuring system.
A decrease in the phase III content and formation of
the phase IV (Figs. 1D–E) were found at the second
stage of the reaction. A decrease in the peak intensity of
the phase III and an increase in the peak intensity of the
phase IV supported the above conclusion. It was clear
that the phase IV formed at this stage was not an
intercalation compound but formation of the complex
occurred. Stoichiometry of the phase IV was determined
by DTA–TG analysis and corresponded to the com-
pound of PbI2(NH3)4.
Table 2 shows the X-ray diffraction data with
assigned Miller indices for the phase IV. The lattice
parameters for the phase IV were calculated:
a ¼ 19:894ð23Þ A, b ¼ 9:345ð27Þ A, c ¼ 7:021ð10Þ A
and V ¼ 1305:35 A3. The lattice symmetry of the phase
IV was found to be orthorhombic.
3. Results and discussion
Fig. 1A shows a diffraction pattern of a pure PbI2
sample. The several diffraction patterns that were
obtained during an X-ray analysis in situ in the course
of interaction between PbI2 and ammonia at
a
The thermal analysis data confirmed the existence
of several compounds in the system of PbI2–NH3.
The results of thermogravimetric study of the phase IV
are shown in Fig. 2B and C. The weight loss
was consistent with the formulation of the starting
composition, i.e. the phase IV, of PbI2(NH3)4. Decom-
position began at the temperatures ToT0 which was
temperature of 285 K are presented in Figs. 1B–E.
Two stages of the reaction can be found. A decrease in
pristine PbI2 content, formation of the intercalated
phases I and II and development of the phase III
(Figs. 1B and C) were revealed at the first stage of the
reaction. A decrease in peak intensity of pristine PbI2,

ARTICLE IN PRESS
G.I. Gurina, K.V. Savchenko / Journal of Solid State Chemistry 177 (2004) 909–915
911
(011)
(102 )
Pb I
2
(110 )
(001)
(103)
(003)
(201)
(111 )
(A)
(100 )
(B)
(C)
(D)
(E)
5
10
15
20
25
30
35
40
45
50
2Θ°
Fig. 1. X-ray diffraction patterns of PbI2 powder sample at a temperature of 285 K before and after the beginning of the reaction between PbI2
and NH3: (A) pristine PbI2; (B) 14 h, (C) 24 h, (D) 48 h; and (E) 72–96 h after the beginning of the reaction.
determined by instability of PbI2(NH3)4 without ammo-
nia medium. Fractions in the curve B (Fig. 2) occurred
at temperatures of T2 ¼ 359 K, T3 ¼ 393 K and
T4 ¼ 423 K. At the temperatures of T2 and T4 the
rate of weight loss of the sample reached maximum
values (Fig. 2C). So the point T2 corresponded to a
maximum temperature of decomposition of the phase
III, and the point T4 to a maximum temperature of
decomposition of the phases II and I. The weight loss at
the point T2 was consistent with the formulation of the
phase III of PbI2(NH3)2.47; the weight loss at the point
T4 to with the formulation of the phases II and I of
PbI2(NH3)1.3. Probably the difference between the
phases II and I was due to the orientation of the NH3
molecules in the gallery space of the layered structure of
PbI2. The phase III differed from phases I and II in an

ARTICLE IN PRESS
G.I. Gurina, K.V. Savchenko / Journal of Solid State Chemistry 177 (2004) 909–915
912
Table 1
X-ray data for the phase III—PbI2(NH3)2.47
Table 2
X-ray data for the phase IV—PbI2(NH3)4
h k l
dOBS (A) dCAL (A) dOBS ꢁ dCAL (A) I=I0 (%) 2YOꢂ BS
h k l
dOBS (A) dCAL (A) dOBS ꢁ dCAL (A) I=I0 (%) 2YOꢂ BS
1 1 0 7.557
0 2 0 6.021
%
2 0 1 4.979
7.58314
6.03066
4.97658
4.26993
4.19422
3.99434
3.84223
3.83840
3.67957
3.66096
3.59128
3.02942
3.01731
2.96678
2.93816
2.77773
2.78344
2.67899
2.57888
2.34453
2.34304
2.34168
2.28281
2.28787
2.17620
2.14838
2.08618
ꢁ0.02559
ꢁ0.00941
0.00239
78.1
15.7
58.8
37.2
34.3
62.7
84.3
11.70
14.70
17.80
20.78
21.10
22.23
23.18
—
0 1 1 5.629
1 1 1 5.386
3 0 1 4.836
4 0 1 4.062
0 2 1 3.903
2 0 2 3.310
5.61348
5.40252
4.82096
4.05841
3.89001
3.31048
3.31560
3.24244
3.24605
3.11514
3.12048
2.84747
2.84195
2.73751
2.74185
2.70126
2.63240
2.63433
2.52337
2.48670
2.44435
2.20321
2.21040
2.20699
2.20359
2.20888
2.10839
2.10998
2.04778
1.92882
0.01574
ꢁ0.01647
0.01523
42.8
53.3
36.8
40.4
100.0
32.3
—
15.73
16.45
18.33
21.86
22.77
26.91
—
0 1 2 4.271
1 2 1 4.207
%
2 0 2 3.995
0.00126
0.01292
0.00142
0.00322
0.01254
ꢁ0.00019
ꢁ0.00532
ꢁ0.00393
ꢁ0.00753
0.00029
2 0 1 3.834
—
ꢁ0.00812
ꢁ0.00429
0.01022
6 0 0
1 1 2 3.239
5 1 1
0 3 0 3.115
2 1 2
0 3 1 2.844
7 0 0
2 3 1 2.735
4 1 2
—
%
2 2 1
—
15.6
—
27.52
—
0 3 1 3.690
2 1 1 3.660
%
1 3 1 3.580
82.3
76.5
23.5
78.1
24.10
24.30
24.85
29.50
—
—
ꢁ0.00109
ꢁ0.01119
ꢁ0.00391
0.00819
77.5
—
28.63
—
—
ꢁ0.00505
ꢁ0.00322
0.00230
%
2 0 3 3.025
70.0
—
31.43
—
0 3 2 —
%
3 2 1 2.966
%
2 1 3 2.938
2 3 1 2.778
%
3 2 2 —
1 4 1 2.677
%
2 4 1 2.581
%
1 1 4 2.342
—
—
ꢁ0.00023
ꢁ0.00021
ꢁ0.00002
ꢁ0.00573
ꢁ0.00228
0.00205
77.5
40.2
13.7
30.10
30.40
32.20
—
ꢁ0.00252
ꢁ0.00687
ꢁ0.00662
ꢁ0.00142
ꢁ0.00335
ꢁ0.00266
0.00036
19.1
—
2.7
32.72
—
—
2 2 2 2.695
5 0 2 2.631
33.22
34.05
—
—
89.2
—
58.8
50
33.45
34.73
38.40
—
7 0 1
—
6 2 1 2.521
8 0 0 2.487
4 2 2 2.444
1 4 1 2.207
30.2
12.2
90.4
79.9
—
35.59
36.08
36.74
40.86
—
ꢁ0.00224
ꢁ0.00076
0.00061
100.0
—
—
1 4 2
1 5 0
—
—
0.00005
0.00355
—
39.40
—
0 0 4 2.285
2 0 3
3 2 2 2.176
0.00230
87.5
—
9 0 0
3 0 3
3 4 0
7 0 2
—
—
—
—
ꢁ0.00364
ꢁ0.00022
0.00318
—
ꢁ0.00276
0.00000
0.00011
—
—
—
—
46.9
50.0
21.9
41.46
42.02
43.35
%
1 5 2 2.148
1 0 4 2.086
ꢁ0.00212
0.00024
—
29.6
—
—
42.85
—
ꢁ0.00058
9 0 1 2.109
4 3 2
—
ꢁ0.00135
0.00082
0.00007
2 2 3 2.049
4 2 3 1.929
12.2
30.1
44.17
47.07
increased ammonia content and another type of cell
symmetry.
Endothermic effect was manifested during the outflow
of ammonia from a sample, and on the DTA traces the
maximums were fixed at the temperatures T2 and T4
(Fig. 2D). The temperature region T02T2 corresponds
to the transition from the phase IV to the phase III, and
the region T22T4 to the transition from the phase III to
the phases II and I. In the temperature region T42T5 the
transition to a pristine PbI2 structure occurred.
Curve A shown in Fig. 2 was obtained during a
differential scanning calorimetry (DSC) study of
PbI2(NH3)4 sample. In the curve there was a single
endothermic peak at the temperature of T4 ¼ 423 K
which indicated an deammoniation process in the
sample. An absence of any peak at lower temperatures
showed that ammonia molecules persisted in the sample
at temperatures ToT3: Evidently, at those temperatures
the ammonia concentration in a sealed ampoule with the
sample was higher than the threshold concentration of
NH3 at the beginning of decomposition. At a higher
temperature an increase in the threshold concentration
occurred. At temperatures T4T3 the threshold con-
centration exceeded the ammonia concentration in the
ampoule, and deammoniation process became possible.
The intercalation threshold in PbI2 for various amines
50
40
30
20
10
0
endo
∆H
A
B
C
D
T
T
2
0
T
4
T
1
T
3
T
5
300
350
450
400
T/K
500
Fig. 2. Data of thermal analysis for the PbI2(NH3)4 samples: (A)
differential scanning calorimetric curve; (B) thermogravimetric curve;
(C) derived from the slope of the curve B; and (D) DTA curve.

ARTICLE IN PRESS
G.I. Gurina, K.V. Savchenko / Journal of Solid State Chemistry 177 (2004) 909–915
913
and the dependence of threshold on temperature were
studied earlier [10,17].
An enthalpy (DH) of formation of PbI2(NH3)4 was
determined from the DSC data, and was equal to
20.8 kJ molꢁ1. This value was close to that of other
intercalated PbI2 compounds [9,18].
films of PbI2. These changes of vibrational spectra of
incorporated amines were a typical manifestation of the
fact of interaction between PbI2 and amine intercalates
[5,7,12,22]. In the works [5,7] the fact of charge transfer
interaction between atom of Pb and free electron pair of
nitrogen atom was ascertained for the compounds of
PbI2 intercalated by amines.
To explore the changes of vibrational spectra of
incorporated NH3 molecules in NH3–PbI2 compounds,
an IR spectroscopic study in the range of 400–
New modes at 3307 cmꢁ1 for PbI2(NH3)2.47 and at
3286 cmꢁ1 for PbI2(NH3)4 were found in the range of
n3ðNHÞ: The H–N–H torsional mode at 628 cmꢁ1 was
slightly shifted to 624 cmꢁ1 for PbI2(NH3)2.47, and two
new modes at 629 cmꢁ1 and 611 cmꢁ1 were found for
PbI2(NH3)4. The mode of NH4+ was not observed
which was also pointed out in the work [12], where IR
spectrum in the range of 400–4000 cmꢁ1 was presented.
For PbI2(NH3)2.47 and PbI2(NH3)4 the values of the
shift in absorption band of symmetric n1ðNHÞ mode
were essentially greater than those of the antisymmetric
n3ðNHÞ mode (Table 3). A similar effect was revealed
during transition from gaseous to crystalline ammonia,
when hydrogen bonds were formed by free electron pair
of nitrogen atom and atom of hydrogen [29]. During
selective adsorption of ammonia molecules on a surface
[30], when the interaction between surface cations and
free electron pair of nitrogen atom of NH3 mostly
occurred, an inverse effect was observed, namely, shift
of n3ðNHÞ mode exceeded shift of n1ðNHÞ mode. A
similar inverse effect was revealed earlier [9,22] during
intercalation of PbI2 by some amines: aniline,
p-toluidine, hexylamine and p-nitroaniline (Table 4).
4000 cmꢁ1, where the semiconductor matrixPbI
is
2
transparent, was carried out. The changes of IR spectra
of samples were recorded during deammoniation of
PbI2(NH3)4 at a temperature of 285 K. During transi-
tion from PbI2(NH3)4 to the phase III the color of the
sample changed from white to pale yellow. Parts of IR
spectra of the PbI2(NH3)4 and PbI2(NH3)2.47 com-
pounds during the deammoniation process are presented
in Figs. 3A–C. Fig. 3D shows a part of IR spectra of
gaseous NH3 within the same region of wavenumbers.
Symmetric n1ðNHÞ and antisymmetric n3ðNHÞ modes of
the N–H bond of gaseous ammonia at 3333 and
3444 cmꢁ1 were shifted: (i) to 3320 and 3433 cmꢁ1
for PbI2(NH3)2.47 and (ii) to 3307 and 3427 cmꢁ1 for
PbI2(NH3)4, respectively. Observed changes for
PbI2(NH3)2.47 are in good agreement with the data of
the work [12] for intercalated samples of textured thin
D
9.0
Table 3
Changes in vibrational modes of NH3 in the compounds with PbI2
[this work] and in crystal NH3 [29]
n3 (cmꢁ1
)
Dn3 (cmꢁ1
)
n1 (cmꢁ1
)
Dn1 (cmꢁ1
)
C
Gaseous NH3
PbI2(NH3)2.47
PbI2(NH3)4
3444
3433
3427
3333
3320
3304
3336
3223
11
17
13
29
6.0
Gaseous NH3 [29] 3444
Crystal NH3 [29] 3378
66
113
B
3.0
Table 4
Changes in vibrational modes of some amines in the compounds with
PbI2 [9,22]
A
n3 (cmꢁ1
)
Dn3 (cmꢁ1
)
n1 (cmꢁ1
)
Dn1 (cmꢁ1
)
Aniline
PbI2–aniline
p-Toluidine
3450
3320
3420
3300
3410
3320
3480
3375
3260
3340
3225
3320
3260
3360
3225
130
120
90
115
115
60
0
3300
3200
-1
PbI2–p-toluidine
Hexylamine
PbI2–hexylamine
p-Nitroaniline
Wavenumber / cm
Fig. 3. Parts of infrared spectra: (A) of ammonia in the PbI2(NH3)4
sample; (B) of ammonia in the sample during the transition from
PbI2(NH3)4 to PbI2(NH3)2.47; (C) of ammonia in the PbI2(NH3)2.47
sample; and (D) of gaseous ammonia.
PbI2–p-nitroaniline 3285
195
135

ARTICLE IN PRESS
G.I. Gurina, K.V. Savchenko / Journal of Solid State Chemistry 177 (2004) 909–915
914
The anomalous shifts of n3ðNHÞ and n1ðNHÞ modes of
ammonia in comparison with the shifts for other amines
can be caused by the absence of radicals in the ammonia
molecule, the radicals imposing steric restrictions on
interaction between atom of hydrogen of the N–H bond
and electron-donating atom of iodine.
possible in part by Grants UA9200 and UA9000 from
the International Science Foundation.
References
The experimental results obtained can be explained by
the existence of the interaction both between hydrogen
atom of NH3 and iodine atom as well as between Pb
cation and nitrogen atom during the formation of the
compounds PbI2 with NH3. That is in good agreement
with the data of the works [10,11] where modelling the
changes in the band structure of PbI2 during intercala-
tion resulted in the conclusion that interaction between
the iodine 5pz electron and intercalate substantially
contributed to the changes in band structure of PbI2.
[1] A.I. Rybalko, V.K. Miloslavsky, Opt. Spectrosc. (Sov. Opt.
Spectrosc.) 41 (1976) 252–256.
[2] V.M. Koshkin, V.V. Kukol, A.P. Milner, Yu.R. Zabrodski, K.A.
Katrunov, Fiz. Tverd. Tela (Sov. Solid Slate Phys.) 19 (1977)
1608–1612.
[3] K.A. Katrunov, V.M. Koshkin, A.P. Milner, S.I. Shevchenko,
Fiz. Tverd. Tela (Sov. Solid Slate Phys.)
531–534.
4
(1978)
[4] V.M. Koshkin, K.A. Katrunov, Pisma Zh. Eksp. Teor. Fiz. 29
(1979) 205–209.
[5] V.M. Koshkin, Izv. Akad. Nauk Latv. SSR 6 (1981) 90–98.
[6] Yu.R. Zabrodski, K.A. Katrunov, V.M. Koshkin, Fiz. Tverd.
Tela (Sov. Solid State Phys.) 25 (1983) 908–911.
[7] K.A. Katrunov, V.M. Koshkin, V.M. Kulakov, Ukr. Fiz. Zh.
(Ukr. J. Phys.) 27 (1982) 226–227.
4. Conclusions
[8] G.I. Gurina, V.D. Evtushenko, O.A. Muraeva, V.P. Ignatyuk,
V.M. Koshkin, Ukr. Khim. Zh. (Ukr. J. Chem.) 51 (1985)
1154–1158.
The consequent changes in the crystal structure of
PbI2 during incorporating NH3 molecules and the
changes in vibrational spectra of incorporated NH3
molecules during changing stoichiometry of the PbI2–
NH3 complexwere studied. The following four com-
pounds were found: PbI2(NH3)1.3 (I and II),
PbI2(NH3)2.47 (III) and PbI2(NH3)4 (IV). Under the
conditions of our experiment three phases PbI2(NH3)1.3
(I and II) and PbI2(NH3)2.47 were intermediated phases,
and the phase PbI2(NH3)4 in ammonia atmosphere at a
pressure of 760 Torr and at room temperature was a
thermodynamic stable phase. The formation of the
complexcompound PbI 2(NH3)4 passed through two
stages. Two compounds PbI2(NH3)1.3 with the lattice
constants a1 ¼ 4:92 A, c1 ¼ 7:62 A and a1 ¼ 4:92 A,
[9] G.I. Gurina, Ph.D. Thesis, Kharkov State University, 1987.
[10] R. Al-Jishi, C.C. Coleman, R. Treece, H. Goldwhite, Phys. Rev.
B 39 (1989) 4862.
[11] V. Mehrotra, S. Lombardo, M.O. Tompson, E.P. Giannelis,
Phys. Rev. B 44 (1991) 5790–5876.
[12] R.F. Warren, W.Y. Liang, J. Phys.: Condens. Matter 5 (1993)
6407–6418.
[13] C.C. Coleman, B. Magness, P. Melo, H. Goldwhite,
W. Tikkanen, Q. Tham, K. Pham, R. Jacubinas, R.B. Kaner,
R.E. Treece, J. Phys. Chem. Solids 57 (6–8) (1996)
1153–1158.
[14] V.M. Koshkin, E.E. Ovechkina, D.V. Tolmachev, O.V.
Yurchenko, A.P. Nekrasov, Funct. Mater. 6 (1999) 77–81.
[15] M. Gallegos, B. Magness, W. Tikkanen, H. Goldwhite, T. Berhe,
G. Coyne, R. Johnson, C.C. Coleman, Annual American Physical
Society March Meeting 2002, Indianapolis, IN, USA, March
18–22, 2002, p. X24010.
%
c2 ¼ 7:49 A in P3ml space group and the PbI2(NH3)2.47
[16] H. Tajali, R. Kharadmand, S. Sharif, The 19th Annual Iranian
Physics Conference, Iranian Physics Society, Tehran, Zanjan,
Iran, May 2002, p. 216.
compound with the lattice constants a ¼ 10:238ð11Þ A,
b ¼ 12:061ð8Þ A, c ¼ 9:587ð8Þ A, b ¼ 107:73ð7Þꢂ in
monoclinic system were formed at the first stage of the
reaction. At the second stage of the reaction the
PbI2(NH3)4 compound with the lattice constants
a ¼ 19:894ð23Þ A, b ¼ 9:345ð27Þ A, c ¼ 7:021ð10Þ A in
orthorhombic system was formed. Anomalous shifts of
symmetric n1ðNHÞ and antisymmetric n3ðNHÞ modes of
the N–H bond of PbI2(NH3)2.47 and PbI2(NH3)4 in
comparison with the shifts for other compounds PbI2
with amines were found.
[17] G.I. Gurina, V.D. Evtushenko, A.Yu. Kobyakov, V.M. Koshkin,
Teor. Eksp. Khim. (Ukr. J. Theor. Eksp. Chem.) 21 (1985)
757–759.
[18] G.I. Gurina, V.D. Evtushenko, V.M. Verchovod, V.M. Koshkin,
Teor. Eksp. Khim. (Ukr. J. Theor. Eksp. Chem.) 21 (1985)
123–127.
[19] G.I. Gurina, A.Yu. Kobyakov, V.D. Evtushenko, V.M. Koshkin,
Method for the quantitative determination of amines in non-
reducing media, Author Certificate of the USSR, 1991, No.
1684639; Bulleten izobretenii i otkiytii, No. 38, 15.10.1991.
[20] V.M. Koshkin, G.I. Gurina, K.V. Savchenko, J. Photochem.
Photobiol. A: Chem. 64 (1992) 369–373.
[21] G.I. Gurina, K.V. Savchenko, J. Photochem. Photobiol. A:
Chem. 86 (1995) 81–84.
Acknowledgments
[22] G.I. Gurina, V.D. Evtushenko, N.A. Gritskaya, V.M. Koshkin,
Zh. Neorg. Khim. (Sov. J. Inorg. Chem.) 31 (1986) 826–829.
[23] G.I. Gurina, K.V. Savchenko, Teor. Eksp. Khim. (Ukr. J. Theor.
Exp. Chem.) 29 (1993) 88–92.
The authors would like to thank Mr. Verkhovoy L.K.
for his masterful assistance in the X-ray diffraction
study and Mrs. Ponomareva N.V. for her masterful
assistance in the treatment of the X-ray data obtained.
The research described in this publication was made
[24] G.I. Gurina, K.V. Savchenko, V.V. Mussil, Proceedings of the
35th IUPAC Congress, Istanbul, Turkey, 14–19 August 1995,
p. 1292 (Sec. 6).

ARTICLE IN PRESS
G.I. Gurina, K.V. Savchenko / Journal of Solid State Chemistry 177 (2004) 909–915
915
[25] G.I. Gurina, K.V. Savchenko, L.K. Verkhovoy, The First
National Conference on Crystal Chemistry, Chernogolovka,
Russia, 24–29 May, 1998, p. 317 (Part 2).
[28] B. Palosz, W. Steurer, H. Schulz, J. Phys.: Condens. Matter 2
(1990) 5285–5295.
[29] M.E. Jacox, D.E. Milligan, Spectrochim. Acta 19 (1963)
1173.
[26] G.I. Gurina, K.V. Savchenko, The 10th International Symposium
on Intercalation Compounds, Okazaki, Japan, May 30–June 3,
1999.
[30] L.H. Little, in: A.V. Kiselev, V.I. Lygin (Eds.), Infrared Spectra
of Adsorbed Species, Academic Press, London, New York,
1966 (Chapters 11 and 13).
[27] A. Boultif, D. Louer, J. Appl. Cryst. 24 (1991) 987–993.