PT-phase diagram of pyridinium perchlorate

Czarnecki, P.; Wąsicki, J.; Paja̢k, Z.; Goc, Roman; Małuszyńska, H.; Habrylo, S.

doi:10.1016/s0022-2860(96)09378-7

Cited by 24 publications

(40 citation statements)

References 5 publications

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“…For the more voluminous anions, the distance between pyridinium dipoles is larger, thus decreasing the direct electrostatic dipole-dipole interaction energy, which can be balanced by thermal energy already at lower temperature so that the phase transition temperature should be expected to increase with decreasing unit cell volume. This is compatible with the reported increase of transition temperatures under external pressure, 3 but not with the unit cell volume as a function of anion size.…”

Section: Discussionsupporting

confidence: 91%

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Ferroelectricity of Pyridinium Perchlorate, a Molecular Level Point of View

2006

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The behavior of ferroelectric and thermodynamic parameters of pyridinium perchlorate (PyClO(4)) was simulated based on experimental NMR data and properties of the individual constituting ions. Dynamic (2)H NMR spectroscopy was used to investigate the order-disorder character of ferroelectricity in PyClO(4). Quadrupole echo and inversion recovery experiments were performed in the range from 140 to 300 K. The spectra can be simulated by a rotational jump motion of the pyridinium cations about their pseudo-C(6) axis. This confirms that the ferroelectricity of this compound below a first-order phase transition at 248 K is primarily due to the ordering of cations along a ferroelectric axis. In an intermediate phase between 248 and 233 K, the cation-anion sublattice displacement mechanism also gives a small positive contribution to ferroelectricity. In the family of the ferroelectric pyridinium salts, the paraelectric-ferroelectric phase transition temperature increases with the size and polarizability of the constituting anions, suggesting that the main interaction for ferroelectric ordering occurs via an indirect superexchange mechanism, whereas in compounds with small anions of low polarizability the direct dipole-dipole interaction dominates and leads to antiferroelectric order.

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Section: Discussionsupporting

confidence: 91%

“…For PyFCrO 3 and PyReO 4 , the high-temperature phase is paraelectric, the intermediate one is ferroelectric, but the order of the low-temperature phase is antiferroelectric. This demonstrates that the behavior of pyridinium salts is influenced by a delicate balance of numerous factors.…”

Section: Discussionmentioning

confidence: 98%

Ferroelectricity of Pyridinium Perchlorate, a Molecular Level Point of View

2006

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“…Detailed experimental results were summarized in Scheme 2. To pyridine template: the products are a 2D polymer bridged by l 2 -H 2 O and l 3 -ClO 4 or single molecule salt, and the structures are consistent with those in the reported literatures [28,29,34]; for the other amines, they were listed as follows: to 1, 10-phenanthroline: single molecule compound [35], or organic salt [36]; to 2, 2-bipyridine: a 1D polymer bridged by l 2 -ClO 4 [37]; to 3-methylpyridine: 2D polymer bridged by l 2 -H 2 O and l 3 -ClO 4 [29]; to 2-methylpyridine, amino-pyridine or isonicotinonitrile: inorganic compound 2.…”

Section: Empiricalsupporting

confidence: 85%

Synthesis, structure and properties of the first inorganic framework Ba(II) perchlorate polymer with organic template

Qian

2012

Journal of Molecular Structure

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“…In the high-temperature phase (I) the pyridinium cation undergoes reorientation about the same axis among the equivalent potential energy minima. According to the structural study at ambient temperature (phase I), PyHClO 4 crystallises in the trigonal system R3m and its cations and anions are dynamically disordered [18] (Fig. 1).…”

Section: Introductionmentioning

confidence: 99%

Polarisation and Energy Barriers in Ferroelectric Pyridinium Perchlorate

et al. 2008

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Polycrystalline sample of pyridinium perchlorate was studied by NMR method in the temperature range from 133 to 313 K. Assuming a reorientation of pyridinium cations over inequivalent potential energy barriers in the low-temperature and intermediate phases a temperature dependence of an asymmetry parameter was determined from analysis of 2 H line shape. By using the known potential shape and population of its minima, a temperature dependence of the spontaneous polarisation was calculated. The polarisation determined in this way compared with that measured by the pyroelectric effect revealed the mixed type of ferroelectricity in the crystal studied: the order-disorder and displacive one.

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PT-phase diagram of pyridinium perchlorate

Cited by 24 publications

References 5 publications

Ferroelectricity of Pyridinium Perchlorate, a Molecular Level Point of View

Ferroelectricity of Pyridinium Perchlorate, a Molecular Level Point of View

Synthesis, structure and properties of the first inorganic framework Ba(II) perchlorate polymer with organic template

Polarisation and Energy Barriers in Ferroelectric Pyridinium Perchlorate

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