Specific heat and phase transition in [Ni(NH3)6] (BF4)2

Grzybek, T.; Janik, J.A.; Mayer, J.; Pytasz, G.; Rachwalska, M.; Waluga, Thomas

doi:10.1002/pssa.2210160257

Cited by 33 publications

(9 citation statements)

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“…The violet and blue colors were used for 2 was also a subject of investigations performed by Chakravortiet al [3]. The measurements were performed up to 573 K. The authors have found that complete deammination takes place in two steps, which is in a good agreement with our results.…”

Section: Resultssupporting

confidence: 90%

“…The MIR spectra registered for both compounds are very similar to each other. Moreover, they are typical for members of the ammine complexes group [10][11][12] 2 in the 4,000-250 cm -1 wavenumber region were presented in paper [3]. Infrared spectrum (MIR and FIR) registered by us in the 4,000-30 cm -1 wavenumber region is in good agreement with data presented by Chakravorti et al [3].…”

Section: Resultssupporting

confidence: 86%

“…The hexaamminenickel(II) perrhenate was obtained in the manner described in [8,9] 2 were placed in 150 ll platinum crucibles. The measurements were made in a flow of Argon (60 cm 3 min -1 ), within temperature range of 295-1,275 K. The TG measurements were performed at a constant heating rate of 10 K min -1 .…”

Section: Methodsmentioning

confidence: 99%

“…The simultaneous evolved gas analysis (EGA) was performed during the experiments by a joined on-line quadruple mass spectrometer (TG-MS) using a ThermostarBalzers apparatus. The temperature was measured by a Pt-Pt/Rh thermocouple with an accuracy of ±0.5 K. In order to estimate the energy activation for identified decomposition steps further TG runs (with the same conditions but without MS signals) for [Ni(NH 3 2 were placed in 40 ll aluminum partially open crucibles (micro hole preserves constant pressure over the sample). Measurements were performed under constant flow of Argon (80 cm 3 min -1 ) with the heating/cooling rate being equal to 10 K min -1 .…”

Section: Methodsmentioning

confidence: 99%

“…Phase polymorphism of compounds with ClO 4 -and BF 4 -anions and [Ni(NH 3 ) 6 ] 2? cation was intensively investigated over past four decades [1,2]. At room temperature they crystallize in a cubic system, space group No.…”

Section: Introductionmentioning

confidence: 99%

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Comparison of vibrational dynamics, thermal behaviour, and phase transition in [Ni(NH3)4](ReO4)2 and [Ni(NH3)6](ReO4)2

Hetmańczyk

2014

J Therm Anal Calorim

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The differences between thermal and vibrational properties of [Ni(NH 3 ) 4 ](ReO 4 ) 2 and [Ni(NH 3 ) 6 ] (ReO 4 ) 2 are reported. The differential scanning calorimetry revealed that tetraamminenickel(II) perrhenate exhibits, in the temperature range of 300-140 K, one phase transition at ca. T c h = 188 K (on heating) and T c c = 185 K (on cooling). In the case of hexaamminenickel(II) perrhenate, no phase transition was observed in the same temperature region. Thermogravimetric measurements showed that the decomposition proceeds in the two main stages. In the first stage, a complete deammination takes place and next Re 2 O 7 is released. TG measurements showed that NH 3 molecules are not equivalently bonded to central atom. The final and intermediate products of decomposition were analysed by means of infrared spectroscopy. The final product of thermal decomposition of both compounds is nickel(II) oxide. The analysis of far infrared spectra revealed that anions in [Ni(NH 3 ) 6 ](ReO 4 ) 2 have disturbed tetrahedral symmetry, whereas in [Ni(NH 3 ) 4 ](ReO 4 ) 2 they seem to form polymeric chains. The variation of the activation energies of the deammination and decomposition steps of [Ni(NH 3 ) 6 ](ReO 4 ) 2 was calculated through the model-free isoconversional Kissinger-Akahira-Sunose method and model-free Kissinger method. Infrared spectra were calculated by the DFT method and quite a good agreement with the experimental data was obtained.

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Section: Resultssupporting

confidence: 90%

Section: Resultssupporting

confidence: 86%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Comparison of vibrational dynamics, thermal behaviour, and phase transition in [Ni(NH3)4](ReO4)2 and [Ni(NH3)6](ReO4)2

Hetmańczyk

2014

J Therm Anal Calorim

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Spectroscopic study of [Me(NH₃)₆]X₂ compounds. I‐Raman study of phase transitions in [Ni(NH₃)₆](ClO₄)₂ and [Ni(ND₃)₆](ClO₄)₂

Janik

Sarga

Pytasz

et al. 1977

J Raman Spectroscopy

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Temperature dependence of Raman spectra was measured for polycrystalline [Ni(NH3)6](CI04)f and [Ni(NDJ)6](C104)2. Spectroscopic evidence for the phase transition at 173 K was obtained. The phase transition is evident in the splitting of some bands corresponding to the internal C10; ion vibrations and in characteristic intensity dependences of the bands. Some bands also showed a characteristic broadening with increasing temperature, which we interpret as being connected with stochastic reorientations of NH, groups and C10-ions. ' Two bands which were not resolved from the others at the room temperature study' were now evidenced at low temperatures.

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Spectroscopy study of [Me(NH₃)₆]X₂ compounds. II—Low frequency infrared and Raman spectra at various temperatures

Zabińaska

Janik

1977

J Raman Spectroscopy

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Infrared and Raman spectra of [Ni(NH3)6]X2 compounds were measured at temperatures from 80 K to 300 Kin the frequency range below c. 400 cm-'. Besides the simple bands previously reported additional ones were seen, especially at lower temperatures. The broad band which appeared between the lattice vibration and the G(NNiN) deformation vibration was interpreted as partly representing the phonon density distribution from the whole Brillouin zone. Its appearance is induced by crystal imperfections connected with NH3 vacancies. Additional bands between S(NNiN) deformation vibration and v(NiN) stretching, and those above the v(NiN) stretching were interpreted as combination bands in which the lattice vibration combines with the deformation in the former case and with the stretching mode in the latter. A satellite band close to the v(NiN) stretching was interpreted as a combination of the stretching and libration mode of the whole [Ni(NH3)a]2' ion. A model correlation function describing the libration was fitted to the experimental correlation function obtained from the i.r. spectra.

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Specific heat and phase transition in [Ni(NH3)6] (BF4)2

Cited by 33 publications

References 4 publications

Comparison of vibrational dynamics, thermal behaviour, and phase transition in [Ni(NH3)4](ReO4)2 and [Ni(NH3)6](ReO4)2

Comparison of vibrational dynamics, thermal behaviour, and phase transition in [Ni(NH3)4](ReO4)2 and [Ni(NH3)6](ReO4)2

Spectroscopic study of [Me(NH₃)₆]X₂ compounds. I‐Raman study of phase transitions in [Ni(NH₃)₆](ClO₄)₂ and [Ni(ND₃)₆](ClO₄)₂

Spectroscopy study of [Me(NH₃)₆]X₂ compounds. II—Low frequency infrared and Raman spectra at various temperatures

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Specific heat and phase transition in [Ni(NH3)6] (BF4)2

Cited by 33 publications

References 4 publications

Comparison of vibrational dynamics, thermal behaviour, and phase transition in [Ni(NH3)4](ReO4)2 and [Ni(NH3)6](ReO4)2

Comparison of vibrational dynamics, thermal behaviour, and phase transition in [Ni(NH3)4](ReO4)2 and [Ni(NH3)6](ReO4)2

Spectroscopic study of [Me(NH3)6]X2 compounds. I‐Raman study of phase transitions in [Ni(NH3)6](ClO4)2 and [Ni(ND3)6](ClO4)2

Spectroscopy study of [Me(NH3)6]X2 compounds. II—Low frequency infrared and Raman spectra at various temperatures

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Spectroscopic study of [Me(NH₃)₆]X₂ compounds. I‐Raman study of phase transitions in [Ni(NH₃)₆](ClO₄)₂ and [Ni(ND₃)₆](ClO₄)₂

Spectroscopy study of [Me(NH₃)₆]X₂ compounds. II—Low frequency infrared and Raman spectra at various temperatures