Specific heat of solid [Ni (NH3)6] (ClO4)2 in the temperature range from 115 to 300 K

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

doi:10.1002/pssa.2210300166

Cited by 30 publications

(4 citation statements)

References 3 publications

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“…The phase transitions temperatures detected for compounds containing simple anions are the lowest in the series [2 and papers cited therein]. As one could expected exchanging simple anion to the tetrahedral one cause that phase transition are observed at higher temperatures [1,2]. We expected that in the case of hexaamminenickel(II) perrhenate the situation will be analogical i.e.…”

Section: Analysis Of Thermal Decomposition Productsmentioning

confidence: 94%

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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: Analysis Of Thermal Decomposition Productsmentioning

confidence: 94%

“…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%

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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“…In this work, it has been determined that for [Mn(NH 3 The investigated sample is unstable in time and temperature. Thermal gravimetry analysis (TG) and DSC measurement informed us that deammination process begins only just at ca.…”

Section: Resultsmentioning

confidence: 99%

“…All up to now investigated ionic coordination compounds of the type [M(NH 3 [1][2][3][4][5][6]. All of them owned cubic symmetry of the crystal lattice (Fm3m) of the high (room) temperature phase [7].…”

Section: Introductionmentioning

confidence: 99%

Thermal properties of polycrystalline [Mn(NH3)6](ClO4)2

Hetmańczyk

Migdał-Mikuli

et al. 2014

J Therm Anal Calorim

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The X-ray powder diffraction (XRPD) pattern of [Mn(NH 3 ) 6 ](ClO 4 ) 2 at room temperature can be indexed in the regular (cubic) system (Fm3m space group) with lattice cell parameter a = 11.5729 Å and with four molecules per unit cell. The XRPD pattern at 100 K is evidently different, and it indicates lowering of the crystal structure. One phase transition at T h C1 = 143.5 K (on heating) and at T c C1 = 137.6 K (on cooling) was detected by DSC for [Mn(NH 3 ) 6 ](ClO 4 ) 2 in the range of 120-300 K. The following thermodynamic parameters for phase I $ phase II transition were obtained: DH = 3.1 ± 0.2 kJ mol -1 and DS = 21.6 ± 0.3 J mol -1 K -1 . The large value of entropy changes (DS) indicates considerable configurational disorder in the high temperature phase. The presence of 5.9 K hysteresis of the phase transition temperature at T C and sharpness of the heat flow anomaly attest that the detected phase transition is of the first-order type. Appearing of the two new bands (splitting of d s (HNH)F 1u mode) in FT-MIR spectra at the vicinity of 1200 cm -1 suggests that the phase transition undergoes a change of the crystal structure.

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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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Specific heat of solid [Ni (NH3)6] (ClO4)2 in the temperature range from 115 to 300 K

Cited by 30 publications

References 3 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

Thermal properties of polycrystalline [Mn(NH3)6](ClO4)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

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Specific heat of solid [Ni (NH3)6] (ClO4)2 in the temperature range from 115 to 300 K

Cited by 30 publications

References 3 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

Thermal properties of polycrystalline [Mn(NH3)6](ClO4)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

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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