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Phase transitions and properties of 0D hybrid iodoantimonate(III) and iodobismuthate(III) semiconducting ferroics: [C(NH2)3]3Bi2I9 and [C(NH2)3]3Sb2I9. J Mol Struct 2021. [DOI: 10.1016/j.molstruc.2020.129387] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Correlation between crystal structures and polar (ferroelectric) properties of hybrids of haloantimonates(iii) and halobismuthates(iii). Inorg Chem Front 2020. [DOI: 10.1039/d0qi00265h] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Halogenoantimonates(iii) and halogenobismuthates(iii) are a highly versatile class of organic–inorganic hybrid materials, applicable in optoelectronics and switchable dielectric devices.
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Hybrid organic-inorganic bismuth(III)-based material [4-NH2C5H4NH]7[BiCl6]2Cl. Crystal structure, dielectric properties and molecular motions of 4-aminopyridinium cations. J Mol Struct 2019. [DOI: 10.1016/j.molstruc.2018.10.096] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Symmetry breaking structural phase transitions, dielectric properties and molecular motions of formamidinium cations in 1D and 2D hybrid compounds: (NH2CHNH2)3[Bi2Cl9] and (NH2CHNH2)3[Bi2Br9]. Dalton Trans 2019; 48:14829-14838. [DOI: 10.1039/c9dt02916h] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Two organic–inorganic hybrid halobismuthates(iii), (NH2CHNH2)3[Bi2Cl9] (FBC) and (NH2CHNH2)3[Bi2Br9] (FBB), have been prepared with their structures revealed by single-crystal X-ray diffraction at various temperatures.
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Widely used hardly known. An insight into electric and dynamic properties of formamidinium iodide. RSC Adv 2018; 8:26506-26516. [PMID: 35541085 PMCID: PMC9083339 DOI: 10.1039/c8ra03871f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2018] [Accepted: 06/21/2018] [Indexed: 11/23/2022] Open
Abstract
The simple organic crystal formamidinium iodide (FAI) appeared to be a novel semiconducting material in a wide temperature range. The electric properties of FAI and the role of formamidinium cation (FA+) in the molecular mechanism of the solid-to-solid phase transitions (at 345 K (III → II) and 388 K (II → I)) were analysed. The creation of the ferroelastic domain structure in phases III and II was proved on the basis of observation under a polarizing microscope. Moreover, the molecular arrangement of dipolar organic FA+ was studied by 1H NMR (spin-lattice relaxation time) and vibrational spectroscopy supported by density functional theory. The theoretical results show a good agreement with the experimental data. The infrared spectrum in a harmonic approximation was calculated and a comparative vibrational analysis was performed. All used techniques showed that the prototypic phase I exhibits the feature of plastic phase. The simple organic crystal formamidinium iodide (FAI) appeared to be a novel semiconducting material in a wide temperature range.![]()
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Structure and dynamics of [NH 2(CH 3) 2] 3Sb 2Cl 9 by means of 1H NMR relaxometry - quadrupolar relaxation enhancement effects. Phys Chem Chem Phys 2018; 19:11197-11205. [PMID: 28405651 DOI: 10.1039/c7cp00788d] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
1H spin-lattice relaxation experiments have been performed for [NH2(CH3)2]3Sb2Cl9 (tris(dimethylammonium)nonachlorodiantimonate(iii)) in the temperature range of 253-313 K and a broad range of frequencies - from 4 kHz to 40 MHz. From the analysis of quadrupolar relaxation enhancement effects (quadrupolar peaks) associated with 14N nuclei, two lattice sites characterized by different electric field gradient tensors have been revealed. The 14N quadrupolar couplings and asymmetry parameters at these sites differ by a factor of about two. Three motional processes have been identified and attributed to the overall dynamics of the NH2(CH3)2 cations (slow motion), dynamics of the NH2 groups (intermediate motion) and methyl group rotation (fast motion). It has been shown that the slow dynamics is only weakly temperature dependent, while the intermediate and fast motional processes are characterized by activation energies of 2.92 kJ mol-1 and 0.41 kJ mol-1, respectively. The correlation time of the slow dynamics is of the order of μs, while the intermediate dynamics is faster by 2-3 orders of magnitude (depending on temperature). All correlation times have turned out to be independent of the position of the cations in the lattice (they are the same for both lattice sites). The analysis presented in this work is an example of the potential of the quadrupolar relaxation enhancement effects as a method revealing information on the dynamics and structure of solids.
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The lone-pair-electron-driven phase transition and order-disorder processes in thermochromic (2-MIm)SbI 4 organic-inorganic hybrid. Dalton Trans 2017; 46:16605-16614. [PMID: 29165466 DOI: 10.1039/c7dt03622a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The easy to prepare and stable in air (2-methylimidazolium) tetraiodoantimoniate(iii) single-crystals with optical band gap of 2.17(1) eV at room temperature have been synthesized. The crystal structure features one-dimensional [SbI4]-n anionic chains, which are intercepted with stacks of 2MIm+ ions. At 294/295 K, it undergoes a structural phase transition to an incommensurately modulated phase as a result of subtle, lone-pair-electron-driven distortions of the anions. Separately from the anion displacements, the ordering of 2MIm+ countercations takes place over a wide temperature range of the modulated phase. The disorder changes from dynamic to static around 200 K, which affects the crystal structure leading to discontinuities and step-like contraction of the lattice parameters. The material is thermochromic with prominent color changes, from raspberry to yellow at low temperatures. The calculated electronic structures and observed optical properties signify its semiconducting character.
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Flexible ferroelectric organic crystals. Acta Crystallogr A Found Adv 2017. [DOI: 10.1107/s0108767317098932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Fourier transform infrared and Raman spectroscopy in the study of phase transitions in dipyrazolium iodide triiodide: Experimental and theoretical analysis. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2017; 179:83-94. [PMID: 28231482 DOI: 10.1016/j.saa.2017.02.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 02/14/2017] [Indexed: 06/06/2023]
Abstract
The paper presents the Infrared and Raman spectra of the powdered [C3N2H5+]2[I-∙I3-] crystal at the temperature intervals of 11-270K, covering two low-temperature phase transitions: discontinuous at 182/188K (cooling/heating) and continuous at 254K. The research shows that the vibrational states of the pyrazolium cations change significantly during discontinuous phase transition (III→II), while the continuous nature of successive structural transformation is more subtle and displays an insignificant change in the temperature coefficient of numerous vibrations during the II→I PT at 254K. The spectacular changes at Raman spectra above 188K confirm a huge rebuilding of inorganic network from [I-∙I3-] to [I42-]. Additionally, a complete geometry optimization was carried out in the solid state in order to obtain minimum structures and bonding properties. The theoretical results correspond well with the experimental data. Moreover, the infrared spectrum in harmonic approximation was calculated, and a comparative vibrational analysis was performed. CRYSTAL09 vibrational results appear to be in a good agreement with the experimental ones.
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Phase sequence in diisopropylammonium iodide: avoided ferroelectricity by the appearance of a reconstructed phase. Inorg Chem Front 2017. [DOI: 10.1039/c6qi00583g] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Crystals of diisopropylammonium iodide are synthesized, grown and characterized.
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Specific heat anomaly in ferroelectric: Bis(imidazolium) pentachloroantimonate(III) (C3 N2 H5)2[SbCl5]. J Mol Struct 2016. [DOI: 10.1016/j.molstruc.2016.01.030] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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12
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1H NMR relaxometry and quadrupole relaxation enhancement as a sensitive probe of dynamical properties of solids—[C(NH2)3]3Bi2I9 as an example. J Chem Phys 2016; 144:054501. [DOI: 10.1063/1.4940680] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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13
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Structure–property relationships in hybrid (C3H5N2)3[Sb2I9] and (C3H5N2)3[Bi2I9] isomorphs. Inorg Chem Front 2016. [DOI: 10.1039/c6qi00260a] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two hybrid crystals imidazolium iodoantimonate(iii) and iodobismuthate(iii) have been synthesized and characterized in a wide temperature range (100–350 K) by means of X-ray diffraction, dielectric spectroscopy, proton magnetic resonance, FT-IR spectroscopy and optical observations.
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The incommensurately modulated phase in (2-methylimidazolium) tetraiodobismuthate(III) thermochromic organic-inorganic hybrid. Acta Crystallogr A Found Adv 2015. [DOI: 10.1107/s2053273315098514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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15
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Dynamics of [C3H5N2]6[Bi4Br18] by means of 1H NMR relaxometry and quadrupole relaxation enhancement. J Chem Phys 2015; 142:204503. [DOI: 10.1063/1.4919966] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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16
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Periodic and incommensurately modulated phases in a (2-methylimidazolium)tetraiodobismuthate(iii) thermochromic organic–inorganic hybrid. CrystEngComm 2015. [DOI: 10.1039/c5ce00046g] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Incommensurately modulated crystal structure of a (2-methylimidazolium)tetraiodobismuthate(iii) thermochromic organic–inorganic hybrid.
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Unprecedented transformation of [I−·I3−] to [I42−] polyiodides in the solid state: structures, phase transitions and characterization of dipyrazolium iodide triiodide. Dalton Trans 2015; 44:18447-58. [DOI: 10.1039/c5dt02265g] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Dipyrazolium iodide triiodide, [C3N2H5+]2[I−·I3−], has been synthesized and studied by means of X-ray diffraction, differential scanning calorimetry, dielectric measurements, and UV-Vis spectroscopy.
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Dielectric Properties and Characterisation of the Superionic Phase of [C(NH2)3]2SbCl5*[C(NH2)3]Cl (GHCA). ACTA ACUST UNITED AC 2014. [DOI: 10.1515/zna-1995-0916] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
GHCA undergoes four phase transitions at Tc1 = 402 K, Tc2 = 373 K, Tc3 = 162 K, and Tc4 = 146 K. Below Tc3 it possesses pyroelectric properties with the spontaneous polarization vector (Ps) in the ac plane and the maximum along the c axis equal to 8 μC/m2. Dielectric dispersion studies of GHCA show that the main dielectric dispersion connected probably with collective motions of chlorine ions is above 1GHz. For the phase transition at Tc2 to a superionic phase the thermal dilatation and electric conductivity were measured. The anomalies of the electric conductivity at Tc2 and Tc1 were observed with large values of σ(10-3 S/m) above Tc3. The guanidinium cations above Tc2, besides reorientational motions, undergo slow self diffusion.
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Dynamics of ferroelectric bis(imidazolium) pentachloroantimonate(III) by means of nuclear magnetic resonance 1H relaxometry and dielectric spectroscopy. J Phys Chem A 2014; 118:3564-71. [PMID: 24804840 DOI: 10.1021/jp501331c] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Some of haloantimonates(III) and halobismuthates(III) are ferroelectric. Bis(imidazolium) pentachloroantimonate(III), (C3N2H5)2SbCl5 (abbreviation: ICA) is the first example of such compounds with a one-dimensional anionic chain which exhibits ferroelectric properties. The relation between the ionic dynamics and network structure and the ferroelectric features is not clear. Here Nuclear Magnetic Resonance (NMR) (1)H spin-lattice relaxation experiments at 25 MHz are reported for ICA in the temperature range of 80 K-360 K, covering ferroelectric-paraelectric and structural phase transitions of the compound occurring at 180 and 342 K, respectively. The relaxation process is biexponential in the whole temperature range indicating two dynamically nonequivalent types of imidazolium cations. Temperature dependences of both relaxation contributions allow for identifying three motional processes. Two of them are cation-specific - i.e. they are attributed to the two types of imidazolium cations, respectively. The third process involves both types of cations, and it is characterized by much lower activation energy. Moreover, the relaxation data (combined with (1)H second moment measurements) show that the ferroelectric-paraelectric phase transition mechanism is governed, to a large extent, by the anionic network arrangement. The NMR studies are complemented by dielectric spectroscopy experiments performed in the vicinity of the Curie temperature, TC = 180 K, to get insight into the mechanism of the ferroelectric-paraelectric phase transition. The dielectric dispersion data show critical slowing down of the macroscopic relaxation time, τ, in ICA when approaching TC from the paraelectric side, indicating an order-disorder type of ferroelectrics.
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Phenomenological analysis of the phase transitions sequence in the ferroelectric crystal (CH3NH3)5Bi2Cl11 (PMACB). ACTA ACUST UNITED AC 2014. [DOI: 10.1007/s002570050305] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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22
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Proton dynamics at low and high temperatures in a novel ferroelectric diammonium hypodiphosphate (NH4)2H2P2O6 (ADhP) as studied by 1H spin-lattice relaxation time and second moment of NMR line. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2013; 231:54-60. [PMID: 23584536 DOI: 10.1016/j.jmr.2013.03.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 03/02/2013] [Accepted: 03/11/2013] [Indexed: 06/02/2023]
Abstract
Proton spin-lattice relaxation times T1 at 24.7 MHz and 15 MHz and second moment of NMR line have been applied to study molecular dynamics of a novel ferroelectric (NH4)2H2P2O6 (T(c)=178 K) in the temperature range 10-290 K. Low-temperature T1 behaviour below Tc is interpreted in terms of Haupt's theory and Schrödinger correlation time of tunnelling jumps. A shallow T1 minimum observed around 39 K is attributed to the C3 classical motion of "intra" proton-proton vectors of NH3 (ammonium groups NH4(+) may perform stochastic jumps about any of the four C3 symmetry axes). The tunnelling splitting of the ground state vibrational level, (νT)v0, of the same frequency for both ammonium groups was estimated as high as 900 MHz ((ħωT)v0=3.7 μeV). This tunnelling splitting exists only in the ferroelectric phase. Magnetisation recovery is found to be non-exponential in the temperature regime 63-48 K. The temperature of 63 K is the discovered T(tun) above which the probability of stochastic tunnelling jumps equals zero. The T1 relaxation time is temperature independent below 25 K, which is related to a constant value of the correlation time characterising tunnelling jumps according to Schrödinger. The T1 minima observed in the paraelectric phase (204 K at 15 MHz and 213 K at 24.7 MHz) as well as second moment reduction at about 130K are attributed to isotropic motion of all protons.
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Experimental (IR) and theoretical (LDA) studies of the structure and vibrational-reorientational dynamics of ferroelastic 1-aminopyridinium iodide. Chem Phys 2012. [DOI: 10.1016/j.chemphys.2012.07.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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24
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Crystal structure and characterization of a novel ferroelastic ionic crystal: 1-Aminopyridinium iodide (C5H7N2)+I−. Chem Phys Lett 2012. [DOI: 10.1016/j.cplett.2012.03.101] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Crystal structure, thermal, dielectric and vibrational properties of a novel polar crystal: 4-Aminopyridinium-hydrogen maleate-maleic acid, [4-NH2C5H4NH][C4H3O4][C4H4O4]. J Mol Struct 2011. [DOI: 10.1016/j.molstruc.2011.06.040] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Complex molecular dynamics of (CH3NH3)5Bi2Br11 (MAPBB) protons from NMR relaxation and second moment of NMR spectrum. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2011; 211:207-216. [PMID: 21741285 DOI: 10.1016/j.jmr.2011.05.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Revised: 04/12/2011] [Accepted: 05/31/2011] [Indexed: 05/31/2023]
Abstract
Molecular dynamics of a polycrystalline sample of (CH(3)NH(3))(5)Bi(2)Br(11) (MAPBB) is studied on the basis of the proton T(1) (55.2 MHz) relaxation time and the proton second moment of NMR line. The T(1) (55.2 MHz) was measured for temperatures from 20K to 330 K, while the second moment M(2) for those from 40K to 330 K. The proton spin pairs of the methyl and ammonium groups perform a complex stochastic motion being a resultant of four components characterised by the correlation times τ(3)(T), τ(3)(H), τ(2), and τ(iso), referring to the tunnelling and over the barrier jumps in a triple potential, jumps between two equilibrium sites and isotropic rotation. The theoretical expressions for the spectral densities in the cases of the complex motion considered were derived. For τ(3)(H), τ(2), and τ(iso) the Arrhenius temperature dependence was assumed, while for τ(3)(T)-the Schrödinger one. The correlation times τ(3)(H) for CH(3) and NH(3) groups differ, which indicates the uncorrelated motion of these groups. The stochastic tunnelling jumps are not present above the temperature T(tun) at which the thermal energy is higher than the activation energy of jumps over the barrier attributed to the hindered rotation of the CH(3) and NH(3) groups. The T(tun) temperature is 54.6 K for NH(3) group and 46.5 K for CH(3) group in MAPBB crystal. The tunnelling jumps of the methyl and ammonium protons are responsible for the flattening of T(1) temperature dependence at low temperatures. The isotropic tumbling is detectable only from the M(2) temperature dependence. The isotropic tumbling reduces the second moment to 4 G(2) which is the value of the intermolecular part of the second moment. The motion characterised by the correlation time τ(2) is well detectable from both T(1) and M(2) temperature dependences. This motion causes the appearance of T(1) minimum at 130 K and reduction of the second moment to the 7.7 G(2) value. The small tunnelling splitting ω(T) of the same value for the methyl and ammonium groups was estimated as 226 MHz from the Haupt equation or 80 MHz from the corrected by us Haupt equation. These frequencies correspond to 0.93 μeV and 0.34 μeV tunnel splitting energy.
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Vibrational and thermodynamic properties and molecular motions in the incommensurate crystal of morpholinium tetrafluoroborate studied by 1H NMR. Chem Phys 2011. [DOI: 10.1016/j.chemphys.2011.01.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Unprecedented solid-state chemical reaction—from . From centrosymmetric to non-centrosymmetric crystal structure. J SOLID STATE CHEM 2010. [DOI: 10.1016/j.jssc.2010.10.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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31
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Structural characterization, thermal, dielectric and vibrational properties of tris(allylammonium) hexabromoantimonate(III), (C3H5NH3)3SbBr6. Chem Phys 2010. [DOI: 10.1016/j.chemphys.2010.07.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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32
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Unprecedented solid-state chemical reaction - from (C 3N 2H 5) 3SbBr 6·H 2O to (C 3N 2H 5) 5Sb 2Br 11; polymorphism of substrate and products. Acta Crystallogr A 2010. [DOI: 10.1107/s0108767310093670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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33
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Novel anionic water-containing inorganic fragment in [4-NH2PyH]8[Bi2Cl11] [Bi2Cl9(H2O)2]: Structural characterization, thermal, dielectric and vibrational properties. Polyhedron 2010. [DOI: 10.1016/j.poly.2010.03.017] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Complex methyl groups dynamics in [(CH3)4P]3Sb2Br9 (PBA) from low to high temperatures by proton spin-lattice relaxation and narrowing of proton NMR spectrum. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2009; 36:144-150. [PMID: 19853419 DOI: 10.1016/j.ssnmr.2009.09.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2009] [Revised: 09/18/2009] [Accepted: 09/25/2009] [Indexed: 05/28/2023]
Abstract
Molecular dynamics of a polycrystalline sample of [(CH(3))(4)P](3)Sb(2)Br(9) (PBA) has been studied on the basis of the T(1) (24.7 MHz) relaxation time measurement, the proton second moment of NMR and the earlier published T(1) (90 MHz) relaxation times. The study was performed in a wide range of temperatures (30-337 K). The tunnel splitting omega(T) of the methyl groups was estimated as of low frequency (from kHz to few MHz). The proton spin pairs of the methyl group are known to perform a complex internal motion being a resultant of four components. Three of them involve mass transportation over and through the potential barrier and are characterized by the correlation times tau(3) and tau(T)of the jumps over the barrier and tunnel jumps in the threefold potential of the methyl group and tau(iso) the correlation time of isotropic rotation of the whole TMP cation. For tau(3) and tau(iso) the Arrhenius temperature dependence was assumed, while for tau(T)--the Schrödinger one. The fourth motion causes fluctuations of the tunnel splitting frequency, omega(T), and it is related to the lifetime of the methyl spin at the energy level. The correlation function for this fourth motion (tau(omega) correlation time) has been proposed by Müller-Warmuth et al. In this paper a formula for the correlation function and spectral density of the complex motion made of the above-mentioned four components was derived and used in interpretation of the T(1) relaxation time. The second moment of proton NMR line at temperatures below 50K is four times lower than its value for the rigid structure. The three components of the internal motion characterized by tau(T), tau(H), and tau(iso) were proved to reduce the second moment of the NMR line. The tunnel jumps of the methyl group reduce M(2) at almost 0K, the classical jumps over the barrier reduce M(2) in the vicinity of 50K, while the isotropic motion near 150K. Results of the study on the dynamics of CH(3) groups of TMP cation based on the second moment measurements were correlated with those based on T(1) time measurements.
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2,4,6-Trimethylpyridinium perchlorate: Polar properties and correlations with molecular structure of organic–inorganic hybrid crystal. J SOLID STATE CHEM 2009. [DOI: 10.1016/j.jssc.2009.07.055] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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36
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Structural characterization, thermal, dielectric, vibrational properties and molecular dynamics of (C5H5NH)3BiCl6. J Mol Struct 2009. [DOI: 10.1016/j.molstruc.2009.05.034] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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37
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Crystal structure, properties and phase transitions of morpholinium tetrafluoroborate [C4H10NO][BF4]. J Mol Struct 2009. [DOI: 10.1016/j.molstruc.2009.04.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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38
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Dielectric critical slowing down in pentakis(imidazolium) undecabromodibismuthate(III): (C(3)N(2)H(5))(5)Bi(2)Br(11). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:015904. [PMID: 21817235 DOI: 10.1088/0953-8984/21/1/015904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Low frequency dielectric dispersion studies have been carried out for the ferroelectric pentakis(imidazolium) undecabromodibismuthate(III)- (C(3)N(2)H(5))(5)Bi(2)Br(11)-single crystal in the paraelectric phase in the radio-frequency region (100 Hz-1 MHz). The dielectric dispersion, observed for an electric field along the a-axis (P 2(1)/n space group), is characterized by a polydispersive nature close to the Curie temperature (T(c) = 155 K). The dielectric dispersion findings were analyzed accurately with the Cole-Cole formula. In the vicinity of the Curie temperature the process of the dielectric critical slowing down is clearly observed. Such a dynamic dielectric response is characteristic of ferroelectric crystals classified as 'order-disorder' type.
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The phase situation and ferroelectric properties in the mixed crystals [4-NH2PyH][SbCl4(1−x)Br4x]. J Mol Struct 2008. [DOI: 10.1016/j.molstruc.2008.02.050] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Structural and dielectric properties of thiazolium chlorobismuthate(III) and chloroantimonate(III). J Mol Struct 2008. [DOI: 10.1016/j.molstruc.2008.02.048] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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The influence of hydrostatic pressure on the ferroelectric phase transition in (C(3)N(2)H(5))(5)Bi(2)Cl(11). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2008; 20:275231. [PMID: 21694392 DOI: 10.1088/0953-8984/20/27/275231] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Single crystals of pentakis (imidazolium) undecachlorodibismuthate (III); (C(3)N(2)H(5))(5)Bi(2)Cl(11), have been studied by the dielectric method at ambient and hydrostatic pressures. At ambient pressure the crystals undergo a ferroelectric phase transition of order-disorder type at 166 K. The character of the dielectric permittivity anomalies is typical of the ferroelectric phase transition close to second-order type. The magnitude of the Curie constants of paraelectric (C(+)) and ferroelectric (C(-)) phases is of the order of 10(3) and the (C(+))/(C(-)) ratio is near 2. At elevated pressures the maximum dielectric permittivity corresponding to the (T(c)) value gradually decreases with increasing pressure. In addition, above about 15 MPa the dielectric permittivity shows a step-like behaviour as well as a temperature hysteresis, which is typical of first-order phase transitions. The Curie-Weiss constant (C(+)) rapidly increases with increasing pressure, reaching a value of the order of 10(5) at about 181 MPa. The pressure-induced change in the phase transition type is continuous and reversible. The phase boundary has been found to decrease nonlinearly with increasing pressure with the initial slope of dT(c)/dp = -3.9 × 10(-2) K MPa(-1). The results have been discussed within the phenomenological model of phase transitions.
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Erratum to ‘Comment on ‘A novel experimental method: Electrochemical detection of phase transition in ferroelectric single crystals’, Chem. Phys. Lett. 384 (2004) 262’ by K. Ćwikiel and M. Matlak [Chem. Phys. Lett. 438 (2007) 358]. Chem Phys Lett 2008. [DOI: 10.1016/j.cplett.2007.11.041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Dielectric critical slowing down in ferroelectric (C(3)N(2)H(5))(5)Sb(2)Br(11). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2007; 19:406225. [PMID: 22049123 DOI: 10.1088/0953-8984/19/40/406225] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Dielectric dispersion studies have been carried out on the pentakis(imidazolium) undecabromodiantimonate(III), (C(3)N(2)H(5))(5)Sb(2)Br(11), single crystal in the audio-frequency region. It is found that low-frequency dielectric dispersion, observed for the field along the a-axis of the monoclinic symmetry (P 2(1)/n), reveals a polydispersive nature near the paraelectric-ferroelectric phase transition temperature (T(c) = 145 K). The dielectric dispersion results can be fitted with the Cole-Cole formula. Unexpectedly, the mean relaxation frequency obeys the Vogel-Fulcher law with freezing temperature of 143 K. Near the ferroelectric phase transition temperature, the process of dielectric critical slowing down was observed. Such a dynamic dielectric response is characteristic of ferroelectrics with an 'order-disorder' transition mechanism.
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Phase transitions and electric properties of imidazolium chlorobismuthate(III): [C3H5N2]6[Bi4Cl18]. J Mol Struct 2007. [DOI: 10.1016/j.molstruc.2006.06.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Structural characterization, thermal and electric properties of imidazolium bromoantimonate(III):. J SOLID STATE CHEM 2007. [DOI: 10.1016/j.jssc.2006.10.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Crystal structure and phase transitions in dipropylammonium hexachloroantimonate(V): [N(C3H7)2H2][SbCl6]. J Mol Struct 2006. [DOI: 10.1016/j.molstruc.2005.10.058] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Polarization switching in (CH3NH3)5Bi2Cl11 ferroelectric crystals. CRYSTAL RESEARCH AND TECHNOLOGY 2006. [DOI: 10.1002/crat.200510625] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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