The influence of chalcogen atom on conformation and phase transition in chalcogenazinoquinolinium monoiodides

2021 ◽  
Vol 77 (4) ◽  
Author(s):  
Irina Yushina ◽  
Alexander Krylov ◽  
Ivan I. Leonidov ◽  
Vladimir Batalov ◽  
Yu-Sheng Chen ◽  
...  
Keyword(s):  
Phase Transition ◽  
Raman Spectroscopy ◽  
Low Temperatures ◽  
Quantum Chemical ◽  
Stokes Shift ◽  
Chalcogen Atom ◽  
Vibrational Assignment ◽  
X Ray Diffraction ◽  
X Ray ◽  
532 Nm

Crystalline chalcogenazinoquinolinium monoiodides, where the chalcogen atom is oxygen and sulfur, have been studied using a combination of X-ray diffraction, Raman and UV-vis spectroscopies and photoluminescence experimental techniques. Periodic quantum-chemical calculations have been performed to characterize the features of electronic structure and vibrational assignment. X-ray diffraction and Raman spectroscopy experiments consistently reveal phase transition of thiazinoquinolinium monoiodide at low temperatures with the decrease of symmetry to P 1. The luminescence study for oxazinoquinolinium monoiodide reveals the excitation maximum at 532 nm and emission at 650 nm with significantly higher intensity than for the thiazinoquinolinium derivative. The studied chalcogenazinoquinolinium monoiodides demonstrate high values of Stokes shift up to 150 nm.

scholarly journals A High-Pressure Investigation of the Synthetic Analogue of Chalcomenite, CuSeO3∙2H2O

Crystals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 643 ◽  
Author(s):  
Javier Gonzalez-Platas ◽  
Placida Rodriguez-Hernandez ◽  
Alfonso Muñoz ◽  
U. R. Rodríguez-Mendoza ◽  
Gwilherm Nénert ◽  
...  
Keyword(s):  
Phase Transition ◽  
Density Functional Theory ◽  
Raman Spectroscopy ◽  
Pressure Dependence ◽  
Density Functional ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray ◽  
Raman Modes

Synthetic chalcomenite-type cupric selenite CuSeO3∙2H2O has been studied at room temperature under compression up to pressures of 8 GPa by means of single-crystal X-ray diffraction, Raman spectroscopy, and density-functional theory. According to X-ray diffraction, the orthorhombic phase undergoes an isostructural phase transition at 4.0(5) GPa with the thermodynamic character being first-order. This conclusion is supported by Raman spectroscopy studies that have detected the phase transition at 4.5(2) GPa and by the first-principles computing simulations. The structure solution at different pressures has provided information on the change with pressure of unit–cell parameters as well as on the bond and polyhedral compressibility. A Birch–Murnaghan equation of state has been fitted to the unit–cell volume data. We found that chalcomenite is highly compressible with a bulk modulus of 42–49 GPa. The possible mechanism driving changes in the crystal structure is discussed, being the behavior of CuSeO3∙2H2O mainly dominated by the large compressibility of the coordination polyhedron of Cu. On top of that, an assignation of Raman modes is proposed based upon density-functional theory and the pressure dependence of Raman modes discussed. Finally, the pressure dependence of phonon frequencies experimentally determined is also reported.

Investigation of the structure and phase transitions of the polymeric inorganic–organic hybrids: [M(Im)4V2O6]∞; M = Mn, Co, Ni, Im = imidazole

2010 ◽  
Vol 67 (1) ◽  
pp. 41-52 ◽  
Author(s):  
Kittipong Chainok ◽  
Kenneth J. Haller ◽  
A. David Rae ◽  
Anthony C. Willis ◽  
Ian D. Williams
Keyword(s):  
Phase Transition ◽  
Low Temperatures ◽  
Stacking Faults ◽  
Local Geometry ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Disordered Phase ◽  
Large Hysteresis ◽  
Close Proximity

The polymeric isomorphous hybrid inorganic–organic vanadium oxide compounds [M(Im)4V2O6]∞, M = Mn, Co, Ni, Im = imidazole, were investigated at various temperatures between 100 and 295 K by single-crystal X-ray diffraction. The crystals all contain two-dimensional polymeric sheets packed perpendicular to c* and are 1:1 disordered in the space group P42/n (Z = 8) at 295 K. The disordered phase is reversibly transformed to an I41/a ordered phase (Z = 32) below 281 K for the Mn compound and below 175 K for the Co compound. Within a localized region of the I41/a phase eight imidazoles are in close proximity and seven of these are hydrogen bonded to framework O atoms. The hydrogen-bond connectivity of six of these ligands is unchanged by the phase transition that allows an inversion of the local geometry using an inversion operator that is a symmetry element of P42/n, but not I41/a. The Mn structure has a well defined phase transition but the Co structure shows a large hysteresis and it was necessary to include stacking faults in the modelling of the Co structure at low temperatures. The Ni structure was shown to be partially twinned, but ordered in the space group P2/n (Z = 8) at 100 K, with two different localized regions each containing four pairs of inversion-related imidazoles, hydrogen bonding to framework O atoms involving eight imidazoles in one region and six imidazoles in the other. Models for the phase transition mechanisms are considered.

Low-temperature phase transition in glycine–glutaric acid co-crystals studied by single-crystal X-ray diffraction, Raman spectroscopy and differential scanning calorimetry

2012 ◽  
Vol 68 (3) ◽  
pp. 287-296 ◽  
Author(s):  
Boris A. Zakharov ◽  
Evgeniy A. Losev ◽  
Boris A. Kolesov ◽  
Valeri A. Drebushchak ◽  
Elena V. Boldyreva
Keyword(s):  
Phase Transition ◽  
Differential Scanning Calorimetry ◽  
Raman Spectroscopy ◽  
Single Crystal ◽  
Glutaric Acid ◽  
Group Symmetry ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray

The occurrence of a first-order reversible phase transition in glycine–glutaric acid co-crystals at 220–230 K has been confirmed by three different techniques – single-crystal X-ray diffraction, polarized Raman spectroscopy and differential scanning calorimetry. The most interesting feature of this phase transition is that every second glutaric acid molecule changes its conformation, and this fact results in the space-group symmetry change from P21/c to P\bar 1. The topology of the hydrogen-bonded motifs remains almost the same and hydrogen bonds do not switch to other atoms, although the hydrogen bond lengths do change and some of the bonds become inequivalent.

ChemInform Abstract: In situ Raman Spectroscopy and X-Ray Diffraction of Pressure-Induced Phase Transition in Columbite CaNb2O6.

ChemInform ◽  
2013 ◽  
Vol 44 (47) ◽  
pp. no-no
Author(s):  
Jing Zhou ◽  
Guanlin Feng ◽  
Liang Li ◽  
Fengxian Huang ◽  
Hongzhi Shen ◽  
...  
Keyword(s):  
Phase Transition ◽  
Raman Spectroscopy ◽  
X Ray Diffraction ◽  
In Situ Raman Spectroscopy ◽  
X Ray ◽  
In Situ Raman

In situ Raman spectroscopy and X-ray diffraction of pressure-induced phase transition in columbite CaNb2O6

2013 ◽  
Vol 579 ◽  
pp. 267-271 ◽  
Author(s):  
Jing Zhou ◽  
Guanlin Feng ◽  
Liang Li ◽  
Fengxian Huang ◽  
Hongzhi Shen ◽  
...  
Keyword(s):  
Phase Transition ◽  
Raman Spectroscopy ◽  
X Ray Diffraction ◽  
In Situ Raman Spectroscopy ◽  
X Ray ◽  
In Situ Raman

Pressure-Induced Phase Transition in CsGeBr3 Studied by X-Ray Diffraction and Raman Spectroscopy

1995 ◽  
Vol 118 (1) ◽  
pp. 20-27 ◽  
Author(s):  
U. Schwarz ◽  
H. Hillebrecht ◽  
M. Kaupp ◽  
K. Syassen ◽  
H.-G. von Schnering ◽  
...  
Keyword(s):  
Phase Transition ◽  
Raman Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray

X-Ray Diffraction Study of the Phase Transition of the ${\rm Si}(111)(\sqrt{3} \times \sqrt{3})\mbox{-Ag}$ Surface

2003 ◽  
Vol 10 (02n03) ◽  
pp. 519-524 ◽  
Author(s):  
Toshio Takahashi ◽  
Hiroo Tajiri ◽  
Kazushi Sumitani ◽  
Koichi Akimoto ◽  
Hiroshi Sugiyama ◽  
...  
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Low Temperatures ◽  
Diffuse Scattering ◽  
Room Temperature ◽  
Bragg Reflection ◽  
Grazing Incidence ◽  
X Ray Diffraction ◽  
X Ray ◽  
Displacive Phase Transition

The structure of the [Formula: see text] surface was studied at both room temperature and a low temperature of 50 K using grazing incidence X-ray diffraction. At low temperatures diffuse scattering was observed in addition to Bragg reflection. Least squares analyses for Bragg reflections using anisotropic Debye–Waller factors show that the structure at 50 K is consistent with an inequivalent triangle (IET) model, while the structure at room temperature is explained by a honeycomb-chained triangle (HCT) model with strong anisotropic Debye–Waller factors. From the temperature dependence of diffuse scattering, the phase transition temperature Tc and critical exponent β were determined to be about 150 K and 0.27. Some Bragg intensities showed discontinuous changes in their first derivatives at Tc. The results favor a displacive phase transition rather than an order–disorder one.

Commensurate-Glass Phase Transitions in Staged Sbcl5-GIC

1982 ◽  
Vol 20 ◽  
Author(s):  
L. Salamanca-Riba ◽  
G. Timp ◽  
L.W. Hobbs ◽  
M.S. Dresselhaus
Keyword(s):  
Phase Transition ◽  
Experimental Study ◽  
Glass Transition ◽  
Phase Transitions ◽  
Electron Diffraction ◽  
Low Temperatures ◽  
Glass Phase ◽  
Driving Mechanism ◽  
X Ray Diffraction ◽  
X Ray

ABSTRACTAn experimental study is reported of the commensurate (√7 × √7)R19.1° to glass phase transition in stages I < n > 4 graphite-SbCl5 using electron and x-ray diffraction. The electron diffraction studies show an in-plane phase transition to a glass at low temperatures. The (00l) x-ray diffraction scans show that the c-axis layered structure of the intercalate is unchanged by the phase transition. A driving mechanism for the commensurate to glass transition is suggested.

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