Phase diagrams of some non-quasi-binary joins of the AlCl 3-BiCl3-NaCl system

Article abstract of DOI:10.1134/S0036023609020259

Phase diagrams of NaAlCl₄-(70.0 mol % AlCl₃ + 30.0 mol % BziCl₃), NaAlCl₄-(34.2 mol % AlCl₃ + 65.8 mol % BiCl₃), and (61.0 mol % AlCl₃ + 39.0 mol % NaCl)-AlCl₃ ? BiCl<

Full text of DOI:10.1134/S0036023609020259

ISSN 0036-0236, Russian Journal of Inorganic Chemistry, 2009, Vol. 54, No. 2, pp. 312–314. © Pleiades Publishing, Ltd., 2009.
Original Russian Text © N.I. Kaloev, A.A. Turieva, 2009, published in Zhurnal Neorganicheskoi Khimii, 2009, Vol. 54, No. 2, pp. 357–359.
PHYSICOCHEMICAL ANALYSIS
OF INORGANIC SYSTEMS
Phase Diagrams of Some Non-Quasi-Binary Joins
of the AlCl3–BiCl3–NaCl System
N. I. Kaloev and A. A. Turieva
Highland State Agrarian University, ul. Kirova 37, Vladikavkaz, 362 000 Russia
Received December 12, 2007
Abstract—Phase diagrams of NaAlCl4–(70.0 mol % AlCl3 + 30.0 mol % BiCl3), NaAlCl4–(34.2 mol % AlCl3
+ 65.8 mol % BiCl3), and (61.0 mol % AlCl3 + 39.0 mol % NaCl)–AlCl3 · BiCl3 non-quasi-binary joins have
been investigated using differential thermal and X-ray powder diffraction analyses. The fields of primary and
joint crystallization of phases and invariant equilibrium temperatures have been determined in these joins. The
structure of the joins has been confirmed by X-ray powder diffraction data.
DOI: 10.1134/S0036023609020259
This work is a continuation of [1–4]. We previously changed with a rate of 3−4 K/min and measured accu-
studied NaAlCl4–AlCl3 · BiCl3, NaAlCl4–BiCl3, and rate to 5°ë K. X-ray powder diffraction analysis was
performed on a DRON-1.0 diffractometer (CuK2 radia-
tion, Ni filter). The 2θ recording rate was 1 deg/min and
the error was 3° deg. For each reflection the intensity
was determined and interplanar spacing was calculated.
Aluminum chloride and bismuth chloride necessary for
the work were prepared by chlorination of electrolytic
metals (99.63 wt % Al, 99.95 wt % Bi) with gaseous
chlorine [7]. Chemically pure grade sodium chloride
was preliminary fused. Storage, weighing, and pouring
of chlorides were performed under conditions exclud-
ing their contact with air moisture. The melting points
of aluminum, bismuth, and sodium chlorides were 194,
236, and 800°ë, respectively. Starting salt mixtures
were melted in sealed vessels fabricated from heat-
resistant or silica glass. The sample size was 2–3 g.
NaAlCl4–NaBiCl4 quasi-binary joins of the AlCl3–
BiCl3–NaCl system [1]. Data on the phase diagrams of
NaAlCl4–(70.0 mol % AlCl3 + 30.0 mol % BiCl3),
NaAlCl4–(34.2 mol % AlCl3 + 65.8 mol % BiCl3), and
(61.0 mol % AlCl3 + 39.0 mol % NaCl)–AlCl3 · BiCl3
non-quasi-binary joins are absent in the literature. Of the
binary subsystems of the AlCl3–BiCl3–NaCl system, the
AlCl3–NaCl, BiCl3–NaCl [5–7], and AlCl3–BiCl3 sys-
tems [8] have been investigated. In the AlCl3–NaCl sys-
tem, there is the NaAlCl4 compound, which congru-
ently melts at 152°ë.
The phase diagram of the BiCl3–NaCl system is char-
acterized by the formation of the congruently melting
compound NaBiCl4 (mp = 243°ë). In the AlCl3–BiCl3
system, the components form the AlCl3 · BiCl3 com-
pound, which melts congruently at 184°ë and is charac-
terized by a polymorphic transformation at 152°ë.
RESULTS AND DISCUSSION
Figure 1 shows the AlCl3–BiCl3–NaCl concentration
triangle with three congruently melting compounds
(NaAlCl4, NaBiCl4, and AlCl3 · BiCl3) on its sides. Solid
lines denote quasi-binary joins 4, 5, and 6, which were
studied previously [1]; dashed lines denote non-quasi-
binary joins 1, 2, and 3. The quasi-binary joins divide the
ternary diagram into four ternary subsystems: AlCl3–
NaAlCl4–AlCl3 · BiCl3, AlCl3 · BiCl3–BiCl3–NaAlCl4,
BiCl3–NaAlCl4–NaBiCl4, and NaBiCl4–NaCl–NaBiCl4
[1]. To determine the character of joins 1, 2, and 3, we used
an experimental method, and by the results of X-ray pow-
der diffraction analysis, we established that they are non-
quasi-binary.
Investigation of phase diagrams based on bis-
muth(III) chloride facilitates the discovery of melts for
growing single crystals of compounds having high ion
conductivity in the solid state [5]. The latter are used as
solid electrolytes in chemical current sources, in elec-
trolytic metallurgy for compositions for deposition of
bismuth–tin coatings on electronic devices, in electro-
lytic refining of bismuth, in production of optical
glasses and enamels, and in chlorine processing of var-
ious types of bismuth raw materials [6].
EXPERIMENTAL
Non-quasi-binary joins 1, 2, and 3 were investigated
by differential thermal (DTA) and X-ray powder dif-
fraction analyses. DTA was carried out on an NTR-64
pyrometer (Pt–Pt/Rh thermocouple). As a reference,
calcined aluminum oxide was used. Temperature was
Join NaAlCl4–(70.0 mol % AlCl3 + 30 mol %
BiCl3) (1). Along this join, we synthesized and investi-
gated by DTA samples of compositions 3.4, 6.9, 10.2,
13.3, 16.8, 19.3, 22.0, 24.8, 27.4, and 30.0 mol % BiCl3.
312

PHASE DIAGRAMS OF SOME NON-QUASI-BINARY JOINS
313
NaCl
T, °C
200
173°
108°
L
154
100
E
6
E
5
L + AlCl3
AlCl3 · BiCl3
+
6
2
NaAlCl
L + NaAlCl4
4
NaBiCl
4
E
1
NaAlCl4 + AlCl3 + AlCl3 · BiCl3
5
E
3
4
4
1
AlCl
E
AlCl BiCl
E
BiCl
3
0
5
10 15 20 25 30
3
2
3
3
3
NaAlCl
BiCl , mol % 70% AlCl
4
3
3
3
mol %
30% BiCl
Fig. 1. Concentration triangle of the AlCl –BiCl –NaCl
3
3
system and joins 1, 2, and 3.
Fig. 2. Phase diagram of the NaAlCl –(70.0 mol % AlCl +
4 3
30.0 mol % BiCl ) join.
3
By the DTA curves of synthesized and annealed samples,
the phase diagram of join 1 was constructed (Fig. 2). This
join is a quasi-binary and eutectic one. Twoliquidus
branches correspond to the primary crystallization of
NaAlCl4 and AlCl3 + AlCl3 · BiCl3. The eutectic has the
composition 13.3 mol % BiCl3 and melts at 108°ë. The
eutectic composition was determined in the course of
construction of the Tammann triangle. The process
NaAlCl4 + AlCl3 + AlCl3 · BiCl3 occurs at the eutectic
point. In the solid state below the eutectic temperature,
three phases coexist, namely, NaAlCl4, AlCl3, and AlCl3 ·
BiCl3. The X-ray powder diffraction analysis of the
13.3 mol % BiCl3 sample showed three phases, namely,
NaAlCl4, AlCl3, and AlCl3 · BiCl3, which verifies the
construction of phase diagram of join 1.
40.6, 46.2, and 50.0 mol % BiCl3. By DTA results, the
phase diagram of non-quasi-binary join 3 was constructed
(Fig. 4), which corresponds to a eutectic-type system. The
eutectic point contains 11.2 mol % BiCl3 and melts at
108°ë. The eutectic composition was determined in the
course of the construction of the Tammann triangle. Two
liquidus branches correspond to the crystallization of
AlCl3, NaAlCl4, and AlCl3 · BiCl3. Below the eutectic
temperature, three phases coexist in the solid state,
namely, AlCl3, AlCl3 · BiCl3, and NaAlCl4.
The structure of the phase diagram of join 3 was
confirmed by X-ray powder diffraction.
T, °C
Join NaAlCl4–(34.2 mol % AlCl3 + 65.8 mol %
BiCl3) (2). Along this join, we synthesized and investi-
gated samples of compositions 5.8, 12.0, 17.9, 24.2, 30.6,
37.1, 43.8, 51.0, 58.0, and 65.8 mol % BiCl3. By the DTA
curves of synthesized and annealed samples, the phase
diagram of join 2 (Fig. 3), which is a non-quasi-binary per-
itectic join, was constructed. The liquidus branches
depicted by solid and dashed lines in the diagram corre-
spond to the crystallization of NaAlCl4, NaAlCl4 + BiCl3,
BiCl3, AlCl3 · BiCl3, AlCl3 · BiCl3 + BiCl3 phases. The
eutectic contains 31.9 mol % BiCl3 and melts at 136°ë.
The eutectic composition was determined in the course of
construction of the Tammann triangle and by X-ray pow-
der diffraction. Below the eutectic temperature, NaAlCl4 +
BiCl3 + AlCl3 · BiCl3 phases coexist, which verifies the
structure of the phase diagram for join 2.
L
200
160°
154
L + AlCl3 · BiCl3+ BiCl3
136°
100
NaAlCl4 + BiCl3 + AlCl3 · BiCl3
0
10 20 30 40 50
BiCl , mol %
6065
NaAlCl
34.2% AlCl
4
3
3
3
65.8% BiCl
Join (61.0 mol % AlCl3 + 39.0 mol % NaCl)–AlCl3 ·
BiCl3 (3). We synthesized and investigated by DTA sam-
ples of compositions 5.2, 10.0, 15.7, 21.2, 26.0, 31.0, 35.8,
Fig. 3. Phase diagram of the NaAlCl –(34.2 mol % AlCl +
4
3
65.8 mol % BiCl ) join.
3
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 54 No. 2 2009

314
KALOEV, TURIEVA
According to the character of melting, the phase
diagrams of non-quasi-binary joins belong to the
eutectic type.
T, °C
200
L
184°
108°
ACKNOWLEDGMENTS
L + AlCl3 · BiCl3
This work was supported by the Program for State
Support of Leading Scientific Schools of Russia,
project no. NSh 829.2003.
114
100
AlCl3 + AlCl3 · BiCl3 + NaAlCl4
REFERENCES
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1330 (1986).
0 5 10 15 20 25 30 35 40 45 50
61% AlCl BiCl , mol % AlCl · BiCl
3
39% NaCl
3. B. G. Korshunov and N. I. Kaloev, Izv. Vyssh. Uchebn.
3
3
3
Zaved., Ser.: Khim. Khim. Tekhnol. 12, 111 (1969).
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Fig. 4. Phase diagram of the (61.0 mol % AlCl + 39.0 mol %
3
NaCl)–AlCl · BiCl join.
3
3
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7 (2), 56 (1940).
To summarize, we continued the investigation of phase
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AlCl3 + 30.0 mol % BiCl3), NaAlCl4–(34.2 mol % AlCl3 +
65.8 mol % BiCl3), and (61.0 mol % AlCl3 + 39.0 mol %
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