Studies of ferroelastic domain structures in (NH4)3H(SO4)2, K3H(SO4)2 and Rb3H(SeO4)2 crystals

Chen, R.H.; Chen, T.M.

doi:10.1016/s0022-3697(96)00097-2

Cited by 14 publications

(4 citation statements)

References 11 publications

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“…Possible space group assignment for a few phases is proposed 9 on the basis of oscillation photos. Even topographic properties of (NH 4 + ) 3 H + (SO 4 2- ) 2 were studied using synchrotron radiation 21 and an optical polarizing microscope. , Powder diffraction studies of phase I of (NH 4 + ) 3 H + (SO 4 2- ) 2 are discussed in ref . Different properties of new compounds obtained by substitution of the cations in (NH 4 + ) 3 H + (SO 4 2- ) 2 by Rb + were examined in refs −29.…”

Section: Introductionmentioning

confidence: 99%

H-Bonding Dependent Structures of (NH₄⁺)₃H⁺(SO₄²^-)₂. Mechanisms of Phase Transitions

et al. 2003

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The role of different H-bonds in phases II, III, IV, and V of triammonium hydrogen disulfate, (NH(4)(+))(3)H(+)(SO(4)(2)(-))(2), has been studied by X-ray diffraction and (1)H solid-state MAS NMR. The proper space group for phase II is C2/c, for phases III and IV is P2/n, and for phase V is P onemacr;. The structures of phases III and IV seem to be the same. The hydrogen atom participating in the O(-)-H(+).O(-) H-bond in phase II of (NH(4)(+))(3)H(+)(SO(4)(2)(-))(2) at room temperature is split at two positions around the center of the crucial O(-)-H(+).O(-) H-bonding, joining two SO(4)(2)(-) tetrahedra. With decreasing temperature, it becomes localized at one of the oxygen atoms. Further cooling causes additional differentiation of possibly equivalent sulfate dimers. The NH(4)(+) ions participate mainly in bifurcated H-bonds with two oxygen atoms from sulfate anions. On cooling, the major contribution of the bifurcated H-bond becomes stronger, whereas the minor one becomes weaker. This is coupled with rotation of sulfate ions. In all the phases of (NH(4)(+))(3)H(+)(SO(4)(2)(-))(2), some additional, weak but significant, reflections are observed. They are located between the layers of the reciprocal lattice, suggesting possible modulation of the host (NH(4)(+))(3)H(+)(SO(4)(2)(-))(2) structure(s). According to (1)H MAS NMR obtained for phases II and III, the nature of the acidic proton disorder is dynamic, and localization of the proton takes place in a broader range of temperatures, as can be expected from the X-ray diffraction data.

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Section: Introductionmentioning

confidence: 99%

H-Bonding Dependent Structures of (NH₄⁺)₃H⁺(SO₄²^-)₂. Mechanisms of Phase Transitions

et al. 2003

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“…Dimer of SeO 4 -H-SeO 4 consists of two slightly distorted SeO 4 tetrahedra connected by the hydrogen bond. The ferroelastic domain structure at low temperature phase was reported by Chen [30]. In the high-temperature superprotonic (paraelastic) phase, the structure of RHSe belongs to the rhombohedral space group R 3m with lattice parameters a = 6.1181(5) Å, c = 22.674 (7) Å and hexagonal unit cell [31].…”

Section: Introductionmentioning

confidence: 69%

Proton dynamics in superprotonic Rb₃H(SeO₄)₂ crystal by broadband dielectric spectroscopy

Ławniczak

Petzelt

Bovtun

et al. 2020

J. Phys.: Condens. Matter

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Broadband dielectric and AC conductivity spectra (1 Hz to 1 THz) of the superprotonic single crystal Rb3H(SeO4)2 (RHSe) along the c axis were studied in a wide temperature range 10 K < T < 475 K that covers the ferroelastic (T < 453 K) and superprotonic (T > 453 K) phases. A contribution of the interfacial electrode polarization layers was separated from the bulk electrical properties and the bulk DC conductivity was evaluated above room temperature. The phase transition to the superprotonic phase was shown to be connected with the steep but almost continuous increase in bulk DC conductivity, and with giant permittivity effects due to the enhanced bulk proton hopping and interfacial electrode polarization layers. The AC conductivity scaling analysis confirms validity of the first universality above room temperature. At low temperatures, although the conductivity was low, the frequency dependence of dielectric loss indicates no clear evidence of the nearly constant loss effect, so-called second universality. The bulk (intrinsic) dielectric properties, AC and DC conductivity of the RHSe crystal at frequencies up to 1 GHz are shown to be caused by the thermally activated proton hopping. The increase of the AC conductivity above 100 GHz could be assigned to the low-frequency wing of proton vibrational modes.

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“…The hydrogen bond character of K 3 H(SO 4 ) 2 was first analyzed to represent a split hydrogen atom feature in the space group ( A 2/ a or C 2/ c ) based on room-temperature X-ray diffraction data. With the examination of the domain structure and ferroelastic behavior in this compound, it was observed that the compound decomposes at about 445 K on heating without going through a structural phase transition in which the author claims to have carefully annealed the samples at temperatures (528 K) below the melting point.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Phase Transition Pathways in X₃H(SO₄)₂ (X = Rb, NH₄, K, Na): Variable Temperature Single-Crystal X-ray Diffraction Studies

Swain

Row

2007

Inorg. Chem.

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Evaluation of phase transitions in a series of hydrogen sulfates (Rb3H(SO4)2, (NH4)3H(SO4)2, K3 H(SO4)2, and Na3H(SO4)2) based on the single-crystal structure analysis has revealed the exact nature of such transitions and has sorted out the various ambiguities involved in earlier literature. Rb3H(SO4)2 at 293 K is C2/c. It is isostructural to its ammonium analogue, (NH4)3H(SO4)2, at room temperature. However, the variable temperature single-crystal diffraction studies indicate that the phase transition mechanism is different. When cooled to 100 K, the structure of Rb3H(SO4)2 remains C2/c. When heated to 350 K, it transforms to C2/m (with double the volume at room temperature), which changes to C2/c (with 4 times the volume at room temperature) at 425 K. The high-temperature (420 K) structural phase transition in (NH4)3H(SO4)2 is shown to be Rm. The structure of Na3H(SO4)2 remains invariant (P21/c) throughout the range of 100-500 K except for the usual contraction of the unit cell at 100 K and expansion at 500 K. The structural phase transitions with temperature for the compound K3H(SO4)2 are very different from those claimed in earlier literature. The hydrogen atom participating in the crucial hydrogen bond joining the two sulfate tetrahedra controls the structural phase transitions at low temperatures in all four compounds. The distortion of the SO4 tetrahedra and the coordination around the metal atom sites control the phase evolution in the Rb compound, while the Na and K analogues show no phase transitions at high temperature, and the NH4 system transforms to a higher symmetry space group resulting in a disorder of the sulfate moiety.

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Studies of ferroelastic domain structures in (NH4)3H(SO4)2, K3H(SO4)2 and Rb3H(SeO4)2 crystals

Cited by 14 publications

References 11 publications

H-Bonding Dependent Structures of (NH₄⁺)₃H⁺(SO₄²^-)₂. Mechanisms of Phase Transitions

H-Bonding Dependent Structures of (NH₄⁺)₃H⁺(SO₄²^-)₂. Mechanisms of Phase Transitions

Proton dynamics in superprotonic Rb₃H(SeO₄)₂ crystal by broadband dielectric spectroscopy

Analysis of Phase Transition Pathways in X₃H(SO₄)₂ (X = Rb, NH₄, K, Na): Variable Temperature Single-Crystal X-ray Diffraction Studies

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Studies of ferroelastic domain structures in (NH4)3H(SO4)2, K3H(SO4)2 and Rb3H(SeO4)2 crystals

Cited by 14 publications

References 11 publications

H-Bonding Dependent Structures of (NH4+)3H+(SO42-)2. Mechanisms of Phase Transitions

H-Bonding Dependent Structures of (NH4+)3H+(SO42-)2. Mechanisms of Phase Transitions

Proton dynamics in superprotonic Rb3H(SeO4)2 crystal by broadband dielectric spectroscopy

Analysis of Phase Transition Pathways in X3H(SO4)2 (X = Rb, NH4, K, Na): Variable Temperature Single-Crystal X-ray Diffraction Studies

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H-Bonding Dependent Structures of (NH₄⁺)₃H⁺(SO₄²^-)₂. Mechanisms of Phase Transitions

H-Bonding Dependent Structures of (NH₄⁺)₃H⁺(SO₄²^-)₂. Mechanisms of Phase Transitions

Proton dynamics in superprotonic Rb₃H(SeO₄)₂ crystal by broadband dielectric spectroscopy

Analysis of Phase Transition Pathways in X₃H(SO₄)₂ (X = Rb, NH₄, K, Na): Variable Temperature Single-Crystal X-ray Diffraction Studies