ISSN 0036-0236, Russian Journal of Inorganic Chemistry, 2008, Vol. 53, No. 8, pp. 1300–1302. © Pleiades Publishing, Ltd., 2008.
Original Russian Text © I.Ya. Zaitseva, I.S. Kovaleva, V.A. Fedorov, 2008, published in Zhurnal Neorganicheskoi Khimii, 2008, Vol. 53, No. 8, pp. 1394–1396.
PHYSICOCHEMICAL ANALYSIS
OF INORGANIC SYSTEMS
Glass Formation along the CsHgBr3–CsPbBr3,
Cs2HgBr4–CsPbBr3, and CsHg2Br5–CsPbBr3 Sections
of the HgBr2–PbBr2–CsBr Ternary System
I. Ya. Zaitseva, I. S. Kovaleva, and V. A. Fedorov
Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences,
Leninskii pr. 31, Moscow, 119991 Russia
Received December 12, 2007
Abstract—Glass formation is studied along the CsHgBr3–CsPbBr3, Cs2HgBr4–CsPbBr3, and CsHg2Br5–
CsPbBr3 sections of the HgBr2–PbBr2–CsBr ternary system. The glass formation region is demarcated. Char-
acteristic temperatures are determined by differential thermal analysis; the ratio Tg/Tm and the Hruby factor HR
for glassy samples are determined. The data are analyzed, and the most promising glass compositions along the
specified sections are determined.
DOI: 10.1134/S0036023608080251
Halide glasses have recently received much atten- sections 1–3 in equilibrium were studied in our previ-
tion on account of their potential for use in IR optics ous works [5, 6].
and communications. Bromide glasses, which are
Glasses were synthesized as follows. Samples with
transparent in the far-IR range (above 20 µm), are par-
compositions lying along sections 1–3 synthesized as
ticularly important [1–3].
above inside Stepanov tubes evacuated to 10–3 Pa were
This work studies glass formation along the heated to temperatures 50–70°ë higher than the melt-
CsHgBr3–CsPbBr3 (1), Cs2HgBr4-CsPbBr3 (2), and ing point of the sample, exposed to this temperature
for 30 min, and then quenched to ice-cold water with
NaCl at about ~–10°ë. Sample sizes were 1 g. Quench-
ing rates were about 100–150 K/s. Quenching resulted
in transparent or semitransparent samples, frequently
yellow, and looking like glasses. Glass formation was
recognized visually (by transparency, characteristic
conchoidal fracture, and other indications) and by DTA
(as characteristic glass transition, crystallization, and
melting temperatures: Tg, Tc, and Tm, respectively). Dif-
ferential thermal analysis was carried out on a pyrome-
ter equipped with Pt–Pt/Rh thermocouples with refer-
ence to Al2O3; heating rates were 8–10 K/min; the tem-
perature determination accuracy was 5 K.
CsHg2Br5-–CsPbBr3 (3) sections of the HgBr2–PbBr2–
CsBr ternary system. Glass formation in this ternary
system has not been mentioned in the literature. In our
previous work [4], we studied glass formation in the
CsBr–HgBr2 and CsBr–PbBr2 binary subsystems of the
HgBr2–PbBr2–CsBr ternary system; we obtained glassy
samples with compositions lying near ternary eutectic
points, which signified the existence of glasses in this
ternary system. Here, we study glass formation along
sections 1–3 in order to determine the glass formation
region in the HgBr2–PbBr2–CsBr system.
EXPERIMENTAL
RESULTS AND DICSUSSION
The starting chemicals used to study glass formation
along sections 1–3 were CsHgBr3, Cs2HgBr4, CsHg2Br5
and CsPbBr3 presynthesized from mercury, lead, and
cesium bromides dried at 100°ë. The synthesis temper-
ature was chosen on the basis of the melting point of
cesium bromide(640°ë), which is the highest melting
point among the constituent bromides. Synthesis lasted
1 day with melt stirring; then, samples were annealed
for 3 days at ~200°ë and then cooled in the switched off
furnace. The melting points of CsHgBr3, Cs2HgBr4,
CsHg2Br5, and CsPbBr3 as determined by differential
thermal analysis (DTA) were 310, 435, 250, and 570°ë,
respectively. The interactions of the components along
Our study of glass formation in the HgBr2–PbBr2–
CsBr system along sections 1–3 showed a feasibility of
synthesizing glassy samples. The results obtained for
each section are considered below.
CsHgBr3–CsPbBr3 section (1) was studied over the
entire range of compositions. The sample compositions
were as follows: 0, 2.5, 7.5, 10, 15, 20, 40, 90, 92.5,
97.5, and 100 mol % CsPbBr3. All samples quenched as
described above were glasses. Glass transition temper-
atures Tg were determined for all samples using DTA;
Tc was determined only for three samples (7.5, 10, and
1300