Non-equivalent water molecules in [Ni(H2O)6](ClO4)2 and in [Ni(D2O)6](ClO4)2 in the thermogravimetric investigations

Rachwalska, M.; Majda, Dorota

doi:10.1007/s10973-006-7497-2

Cited by 5 publications

(2 citation statements)

References 12 publications

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“…The IINS bands were assigned to a water molecule libration of the third kind in [Ni(H 2 O) 6 )] 2+ [1]. Such separation of water molecules into dynamically inequivalent sets was observed by the quasielastic neutron scattering method [8] too, as well as in some thermogravimetric investigations [14].…”

Section: Resultsmentioning

confidence: 75%

FIR Spectra of [Ni(H₂O)₆](ClO₄)₂ and [Ni(D₂O)₆](ClO₄)₂ at Various Temperatures

Rachwalska¹,

Ściesińska²,

Ściesiński³

2006

Zeitschrift Für Physikalische Chemie

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Low frequency vibrations in [Ni(H 2 O) 6 ](ClO 4 ) 2 and [Ni(D 2 O) 6 ](ClO 4 ) 2 were measured by the FIR Fourier Transform Spectroscopy method. They were compared with those obtained by the IINS method. No evidence of proton glass discovered by the IINS was observed via the FIR method. By applying the band contour method, the barrier to rotation U act for H 2 O groups in [Ni(H 2 O) 6 ](ClO 4 ) 2 crystals was determined. A III-II phase transition mechanism was proposed.

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Section: Resultsmentioning

confidence: 75%

FIR Spectra of [Ni(H₂O)₆](ClO₄)₂ and [Ni(D₂O)₆](ClO₄)₂ at Various Temperatures

Rachwalska¹,

Ściesińska²,

Ściesiński³

2006

Zeitschrift Für Physikalische Chemie

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“…Additionally, an extremely small specific heat anomaly shows up at the temperatures ~225 and 168 K for [Ni(H 2 O) 6 ](ClO 4 ) 2 and [Mg(H 2 O) 6 ](ClO 4 ) 2 , respectively. [Mg(H 2 O) 6 ](ClO 4 ) 2 and [Ni(H 2 O) 6 ](ClO 4 ) 2 melt in temperatures above 420 K . However, [Ba(H 2 O) 3 ](ClO 4 ) 2 starts losing water molecules just above 350 K …”

Section: Resultsmentioning

confidence: 99%

Raman light scattering, infrared absorption and DSC studies of the phase transition and vibrational and reorientational dynamics of H₂O ligands and ClO₄^– anions in [Ba(H₂O)₃](ClO₄)₂

Hetmańczyk

Migdał-Mikuli

et al. 2012

J Raman Spectroscopy

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[Ba(H2O)3](ClO4)2 between 90 and 300 K possesses two solid phases. One phase transition of the first‐order type at: TCh = 211.3 K (on heating) and TCc = 204.6 K (on cooling) was determined by differential scanning calorimetry. The entropy change value (ΔS ≈ 15 Jmol–1 K–1), associated with the observed phase transition, indicates a moderate degree of molecular dynamical disorder. Both, vibrational and reorientational motions of H2O ligands and ClO4– anions, in the high‐temperature and low‐temperature phases, were investigated by Fourier transform far‐infrared and middle‐infrared and Raman light scattering spectroscopies. The temperature dependences of the full‐width at half‐maximum values of the bands associated with ρw(H2O) mode, in both infrared (~570 cm–1) and Raman light scattering (~535 cm–1) spectra, suggest that the observed phase transition is not associated with a sudden change of a speed of the H2O reorientational motions. Ligands reorient fast, with correlation time of the order of several picoseconds, with a mean activation energy value Ea = 5.1 kJ mol–1 in both high and low temperature phases. On the other hand, measurements of temperature dependences of full‐width at half‐maximum values of the infrared band at ~460 cm–1, associated with δd(OClO)E mode, and Raman band at ~1105 cm–1, associated with νas(ClO)F2 mode, revealed the existence of a fast ClO4– reorientation in phase I and in phase II, with the Ea(I) and Ea(II) values equal to 8.0 and 6.5 kJ mol–1, respectively. These reorientational motions of ClO4– are slightly distorted at the TC. Fourier transform far‐infrared and middle‐infrared spectra with decreasing of temperature indicated characteristic changes at the vicinity of PT at TC, which suggested lowering of the crystal structure symmetry. All these experimental facts suggest that the discovered phase transition is associated with small change of H2O ligands and somewhat major change of ClO4– anions reorientational dynamics, and with insignificant change of the crystal structure, too. Copyright © 2012 John Wiley & Sons, Ltd.

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Thermal behavior of [Ca(H2O)4](ClO4)2 and [Ca(NH3)6](ClO4)2

Migdał-Mikuli

Hetmańczyk

2007

J Therm Anal Calorim

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Non-equivalent water molecules in [Ni(H2O)6](ClO4)2 and in [Ni(D2O)6](ClO4)2 in the thermogravimetric investigations

Cited by 5 publications

References 12 publications

FIR Spectra of [Ni(H₂O)₆](ClO₄)₂ and [Ni(D₂O)₆](ClO₄)₂ at Various Temperatures

FIR Spectra of [Ni(H₂O)₆](ClO₄)₂ and [Ni(D₂O)₆](ClO₄)₂ at Various Temperatures

Raman light scattering, infrared absorption and DSC studies of the phase transition and vibrational and reorientational dynamics of H₂O ligands and ClO₄^– anions in [Ba(H₂O)₃](ClO₄)₂

Thermal behavior of [Ca(H2O)4](ClO4)2 and [Ca(NH3)6](ClO4)2

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Non-equivalent water molecules in [Ni(H2O)6](ClO4)2 and in [Ni(D2O)6](ClO4)2 in the thermogravimetric investigations

Cited by 5 publications

References 12 publications

FIR Spectra of [Ni(H2O)6](ClO4)2 and [Ni(D2O)6](ClO4)2 at Various Temperatures

FIR Spectra of [Ni(H2O)6](ClO4)2 and [Ni(D2O)6](ClO4)2 at Various Temperatures

Raman light scattering, infrared absorption and DSC studies of the phase transition and vibrational and reorientational dynamics of H2O ligands and ClO4– anions in [Ba(H2O)3](ClO4)2

Thermal behavior of [Ca(H2O)4](ClO4)2 and [Ca(NH3)6](ClO4)2

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FIR Spectra of [Ni(H₂O)₆](ClO₄)₂ and [Ni(D₂O)₆](ClO₄)₂ at Various Temperatures

FIR Spectra of [Ni(H₂O)₆](ClO₄)₂ and [Ni(D₂O)₆](ClO₄)₂ at Various Temperatures

Raman light scattering, infrared absorption and DSC studies of the phase transition and vibrational and reorientational dynamics of H₂O ligands and ClO₄^– anions in [Ba(H₂O)₃](ClO₄)₂