Structural-phase transition in (Cu2Te)2−x(ZnTe)x at high temperature

2021 ◽  
pp. 2150113
Author(s):  
H. B. Gasimov ◽  
R. M. Rzayev
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
High Temperature ◽  
Single Crystals ◽  
Structural Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Range ◽  
Xrd Study ◽  
Xrd Method

Cu2Te single crystal was grown by the Bridgman method. X-ray diffraction (XRD) study of Cu2Te single crystals in the temperature range of 293–893 K was performed and possible phase transitions in the mentioned range of temperature have been investigated. (Cu2Te)[Formula: see text](ZnTe)[Formula: see text] single crystals also were grown with [Formula: see text], 0.05, 0.10 concentrations and structural properties of the obtained single crystals were investigated by the XRD method in the temperature range 293–893 K. Lattice parameters and possible phase transitions in the mention temperature range were determined for (Cu2Te)[Formula: see text](ZnTe)[Formula: see text] single crystals for [Formula: see text], 0.05, 0.10 concentrations.

X-ray diffraction and Raman study of DL-alanine at high pressure: revision of phase transitions

2012 ◽  
Vol 68 (4) ◽  
pp. 412-423 ◽  
Author(s):  
Nikolay A. Tumanov ◽  
Elena V. Boldyreva
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Structural Phase ◽  
Group Symmetry ◽  
Second Phase ◽  
Structural Phase Transitions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Parameters ◽  
Raman Study

The effect of pressure on DL-alanine has been studied by X-ray powder diffraction (up to 8.3 GPa), single-crystal X-ray diffraction and Raman spectroscopy (up to ∼ 6 GPa). No structural phase transitions have been observed. At ∼ 1.5–2 GPa, cell parameters b and c become accidentally equal to each other, but the space-group symmetry does not change. There is no phase transition between 1.7 and 2.3 GPa, contrary to what has been reported earlier [Belo et al. (2010). Vibr. Spectrosc. 54, 107–111]. The presence of the second phase transition, which was claimed to appear within the pressure range from 6.0 to 7.3 GPa (Belo et al., 2010), is also argued. The changes in the Raman spectra have been shown to be continuous in all the pressure ranges studied.

A conformational polymorphic transition in the high-temperature ∊-form of chlorpropamide on cooling: a new ∊′-form

2009 ◽  
Vol 65 (6) ◽  
pp. 770-781 ◽  
Author(s):  
Tatiana N. Drebushchak ◽  
Yury A. Chesalov ◽  
Elena V. Boldyreva
Keyword(s):  
Phase Transition ◽  
High Temperature ◽  
Structural Changes ◽  
Molecular Conformation ◽  
Polymorphic Transition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Parameters ◽  
Temperature Range ◽  
Two Phases

Structural changes in the high-temperature ∊-polymorph of chlorpropamide, 4-chloro-N-(propylaminocarbonyl)benzenesulfonamide, C10H13ClN2O3S, on cooling down to 100 K and on reverse heating were followed by single-crystal X-ray diffraction. At temperatures below 200 K the phase transition into a new polymorph (termed the ∊′-form) has been observed for the first time. The polymorphic transition preserves the space group Pna21, is reversible and is accompanied by discontinuous changes in the cell volume and parameters, resulting from changes in molecular conformation. As shown by IR spectroscopy and X-ray powder diffraction, the phase transition in a powder sample is inhomogeneous throughout the bulk, and the two phases co-exist in a wide temperature range. The cell parameters and the molecular conformation in the new polymorph are close to those in the previously known α-polymorph, but the packing of the z-shaped molecular ribbons linked by hydrogen bonds inherits that of the ∊-form and is different from the packing in the α-polymorph. A structural study of the α-polymorph in the same temperature range has revealed no phase transitions.

X-ray diffraction study revealing phase coexistence in barium titanate stannate

2004 ◽  
Vol 19 (10) ◽  
pp. 2834-2840 ◽  
Author(s):  
Volkmar Mueller ◽  
Horst Beige ◽  
Hans-Peter Abicht ◽  
Christian Eisenschmidt
Keyword(s):  
Phase Transition ◽  
Ferroelectric Phase ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
X Ray ◽  
Temperature Range ◽  
Xrd Study ◽  
Xrd Patterns ◽  
Tetragonal Phase Transition

In this paper, the results of a temperature dependent x-ray diffraction (XRD) study on BaTi0.95Sn0.05O3 (BTS-5) ceramics are compared with dielectric measurements. The orthorhombic-tetragonal phase transition at T2 = 306 K is found to proceed in a considerably wider temperature range than expected from the dielectric anomaly. Although the macroscopic properties of BTS-5 indicate a rather sharp ferroelectric phase transition at Tc = 358K, we observe anomalous XRD-patterns in a 25 K wide temperature range. This is interpreted in terms of mechanically clamped tetragonal and cubic phase, coexisting in the vicinity of Tc in grains with inhomogeneous Sn-distribution.

Reinvestigation of the structure of BaCuSi2O6 – evidence for a phase transition at high temperature

2004 ◽  
Vol 60 (5) ◽  
pp. 491-495 ◽  
Author(s):  
Karine M. Sparta ◽  
Georg Roth
Keyword(s):  
Phase Transition ◽  
High Temperature ◽  
Room Temperature ◽  
Unit Cell Volume ◽  
Structural Phase ◽  
Original Structure ◽  
Crystal Chemical ◽  
X Ray Diffraction ◽  
X Ray ◽  
Barium Copper

Superstructure reflections have been observed in the room-temperature X-ray diffraction pattern of BaCuSi2O6, barium copper disilicate. The tetragonal structure has a fourfold unit-cell volume compared with the original structure determined by Finger et al. [(1989), Am. Mineral. 74, 952–955]. At T s = 610 K BaCuSi2O6 undergoes a structural phase transition upon which the superstructure reflections disappear. The description of the structure in the larger cell removes the crystal-chemical inconsistencies observed for the original structure.

scholarly journals Inorganic Anion Regulates the Phase Transition in Two Organic Cation Salts Containing [(4-Nitroanilinium)(18-crown-6)]+ Supramolecules

2017 ◽  
Author(s):  
Yuan Chen ◽  
Yang Liu ◽  
Binzu Gao ◽  
Chuli Zhu ◽  
Zunqi Liu
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Variable Temperature ◽  
Structural Phase ◽  
High Temperature Phase ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Space Group ◽  
X Ray

Two novel inorganic–organic hybrid supramolecular assemblies, namely, (4-HNA)(18-crown-6)(HSO4) (1) and (4-HNA)2(18-crown-6)2(PF6)2(CH3OH) (2) (4-HNA = 4-nitroanilinium), were synthesized and characterized by infrared spectroscopy, single X-ray diffraction, differential scanning calorimetry (DSC), and temperature-dependent dielectric measurements. The two compounds underwent reversible phase transitions at about 255 K and 265 K, respectively. These phase transitions were revealed and confirmed by the thermal anomalies in DSC measurements and abrupt dielectric anomalies during heating. The phase transition may have originated from the [(4-HNA)(18-crown-6)]+ supramolecular cation. The inorganic anions tuned the crystal packings and thus influenced the phase-transition points and types. The variable-temperature X-ray diffraction data for crystal 1 revealed the occurrence of a phase transition in the high-temperature phase with the space group of P21/c and in the low-temperature phase with the space group of P21/n. Crystal 2 exhibited the same space group P21/c at different temperatures. The results indicated that crystals 1 and 2 both underwent an iso-structural phase transition.

High-temperature X-ray diffraction study of Ag2S-Cu2S system

2020 ◽  
pp. 2150018
Author(s):  
Y. G. Asadov ◽  
Y. I. Aliyev ◽  
A. O. Dashdemirov ◽  
S. H. Jabarov ◽  
T. G. Naghiyev
Keyword(s):  
Thermal Expansion ◽  
Phase Transitions ◽  
High Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermal Expansion Coefficients ◽  
Cubic Phases ◽  
Temperature Ranges ◽  
Expansion Coefficients ◽  
Xrd Method

Single crystals of AgCuS, [Formula: see text], [Formula: see text] and [Formula: see text] compounds were synthesized using the Bridgman method. The crystal structures and phase transitions were studied by X-ray diffraction (XRD) method in the high temperature ranges. The monoclinic, orthorhombic, hexagonal and cubic phases were observed in the temperature range of [Formula: see text]. Thermal expansion coefficients were calculated for different phases according to the lattice parameters. It was determined that the values of thermal expansion coefficients differ in different planes depending on the space group and symmetry.

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