| People | Locations | Statistics |
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| Naji, M. |
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| Motta, Antonella |
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| Aletan, Dirar |
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| Mohamed, Tarek |
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| Ertürk, Emre |
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| Taccardi, Nicola |
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| Kononenko, Denys |
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| Petrov, R. H. | Madrid |
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| Alshaaer, Mazen | Brussels |
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| Bih, L. |
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| Casati, R. |
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| Muller, Hermance |
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| Kočí, Jan | Prague |
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| Šuljagić, Marija |
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| Kalteremidou, Kalliopi-Artemi | Brussels |
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| Azam, Siraj |
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| Ospanova, Alyiya |
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| Blanpain, Bart |
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| Ali, M. A. |
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| Popa, V. |
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| Rančić, M. |
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| Ollier, Nadège |
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| Azevedo, Nuno Monteiro |
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| Landes, Michael |
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| Rignanese, Gian-Marco |
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Czarnecki, Piotr
Adam Mickiewicz University in Poznań
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (18/18 displayed)
- 2022Above-room-temperature ferroelectricity and piezoelectric activity of dimethylglycinium-dimethylglycine chloridecitations
- 2012New ferroelectric: Bis-thiourea pyridinium bromide inclusion compoundcitations
- 2012Structures and phase transitions in a new ferroelectric-pyridinium chlorochromate-studied by X-ray diffraction, DSC and dielectric methodscitations
- 2010The neutron diffraction study, calorimetry and spontaneous polarization of pyridinium perrhenate at 350, 300 and 100Kcitations
- 2009Discovery of an intermediate phase in bis-thiourea pyridinium chloride inclusion compound.citations
- 2009Discovery of an intermediate phase in bis-thiourea pyridinium chloride inclusion compoundcitations
- 2008Redetermination of the structure and dielectric properties of bis(thiourea) pyridinium iodide - A new ferroelectric inclusion compoundcitations
- 2007Phase transitions in ferroelectric pyridinium periodide under high pressurecitations
- 2006Structure, phase transitions and dielectric properties of a new inclusion compound of bis-thiourea pyridinium nitrate saltcitations
- 2006Dielectric response of the relaxor ferroelectric Pb(Mg<inf>1/3</inf>Nb <inf>2/3</inf>)O<inf>3</inf> in the nonergodic state after a DC electric field is turned off
- 2005Decoupling of the order-disorder and displacive contributions to the phase transition in NH<inf>4</inf>H(ClH<inf>2</inf>CCOO)<inf>2</inf>citations
- 2005Compositional and pressure effects on the phase transition in ferroelectric NH<inf>4</inf>H(ClH<inf>2</inf>CCOO)<inf>2</inf>
- 2003Effect of hydrostatic pressure on the dielectric response of Pb(Mg 1/3Nb2/3)O3 relaxorcitations
- 2003The neutron diffraction study of pyridinium periodate at 352, 300 and 100 Kcitations
- 20012-5 pyrochlore relaxor ferroelectric Cd<inf>2</inf>Nb<inf>2</inf>O<inf>7</inf> and its Fe<sup>2+</sup>/Fe<sup>3+</sup> modificationscitations
- 2001Structure and dynamics of ferroelectric pyridinium periodatecitations
- 2000High pressure study of cation dynamics in pyridinium Perchloratecitations
- 2000Structure and dielectric properties of ferroelectric pyridinium perrhenate crystalscitations
Places of action
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article
Structure, phase transitions and dielectric properties of a new inclusion compound of bis-thiourea pyridinium nitrate salt
Abstract
<p>A structure of a new inclusion compound of bis-thiourea pyridinium nitrate salt C<sub>5</sub>H<sub>6</sub>N<sup>+</sup>NO<sub>3</sub><sup>-</sup> 2[CH <sub>4</sub>N<sub>2</sub>S] was determined by single-crystal X-ray diffraction method at 293 K, 250 K and 150 K. In high temperature phase the compound crystallizes in orthorhombic system, the two low-temperature phases are monoclinic. The sequence of phases is: Pbnm ⇒ P2<sub>1</sub>/c ⇒ P2<sub>1</sub>. In the orthorhombic form (I) the a axis is doubled in respect to the monoclinic forms and pyridinium and nitrate ions are partially disordered. Both low-temperature monoclinic phases (II) and (III) are ordered but twinned by pseudomerohedry. In all three phases the host lattice is built of ribbons of hydrogen-bonded thiourea molecules and nitrate anions forming channels in which the guests pyridinium cations are located. Each ribbon consists of two crystallographically independent thiourea molecules and nitrate ions. Four ribbons form a channel parallel to the c axis with approximately square cross-section. In the channel there is a stack of pyridinium cations, which planes form an inclination angle with the channel axis. The angle varies from about 90° in disordered phase I to 60° in well ordered phase (III). The dielectric spectroscopy measurements were performed on the polycrystalline sample with HP-4291A impedance analyser in the frequency range 1 MHz-1 GHz. The dielectric measurements reveal that two phase transitions occur at T<sub>1</sub> = 287 K and at T<sub>2</sub> = 217 K. The phase transition at T<sub>2</sub> = 287 K is of the first order with the thermal hysteresis of 10 K at cooling and heating. The phase transition at 217 K is of the second order and the dielectric anomaly suggests the ferroelectric-paraelectric phase transition. The dielectric relaxation observed below T<sub>2</sub> are caused by the pyridinium cation reorientation. The dielectric relaxation time changes with the temperature according to Arrhenius low and the activation energy of the relaxation process is about 14 kJ/mol. © by Oldenbourg Wissenschaftsverlag.</p>