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, J.A.; Sarga, T.; Pytasz, G.; Sokotowski, J.

doi:10.1002/jrs.1250060306

Cited by 12 publications

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References 11 publications

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“…approach the phase transition points, which are 8 0 K for [Ni(NH3)6]C12, 3 stretching mode v(NiN)A1, is inactive in both the i.r. and Raman spectra for the cubic phase.…”

Section: Additional Bandsmentioning

confidence: 99%

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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“…approach the phase transition points, which are 8 0 K for [Ni(NH3)6]C12, 3 stretching mode v(NiN)A1, is inactive in both the i.r. and Raman spectra for the cubic phase.…”

Section: Additional Bandsmentioning

confidence: 99%

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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Spectroscopy study of [Ni(NH₃)₆]X₂ compounds. III reorientational correlation times of NH₃ and ClO₄ groups in [Ni(NH₃)₆](ClO₄)₂

Janik

1978

J Raman Spectroscopy

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By applying the Raman band profile analysis method, reorientational correlation times of NH3 groups and (ClO,)-ions in [Ni(NH&l (CI04)2, have been obtained. These times are of the order of psec at mom temperature. They increase with decreasing temperature. NH3 reorientations do not show any significant changes when the temperature passes the phase transition region (173 K-143 K). (Clod)-reorientations, on the other hand stop abruptly at the phase transition in 173 K. A comparison with IR and neutron scattering results leads to a choice of 120" angular jumps as the NH3 reorientational model.

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Investigation of the phase situation in polycrystalline [Mg(NH3)6](ClO4)2 by adiabatic calorimetry and X-ray diffraction methods

Migdał-Mikuli

Mikuli

Rachwalska

et al. 1978

Phys. Stat. Sol. (a)

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Calorimetric measurements are performed for [Mg(NH3)6] (ClO4)2. Two anomalies in the specific heat curve are found: a small one at 139.5 K and a large one at 154.35 K. The entropy changes associated with these anomalies are (1.30 ± 0.07) and (7.26 ± 0.28) cal/mol K, respectively. X‐ray diffraction measurements are also made for this substance. They show that the occurrence of these anomalies is due to structural transformations. At 154.35 K there is an enantiomorphic phase transition: the cubic phase (space group Fm3m) transforms into the monoclinic phase (space group P21/n). At 139.5 K there is further ordering of the monoclinic structure. A comparison of the results obtained now for [Mg(NH3)6] (ClO4)2 and results obtained earlier for [Ni(NH3)6](ClO4)2 demonstrates the complete analogy between the two substances and seems to point out the dominating role of the ClO 4− anion in both the phase transitions.

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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

Cited by 12 publications

References 11 publications

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

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

Spectroscopy study of [Ni(NH₃)₆]X₂ compounds. III reorientational correlation times of NH₃ and ClO₄ groups in [Ni(NH₃)₆](ClO₄)₂

Investigation of the phase situation in polycrystalline [Mg(NH3)6](ClO4)2 by adiabatic calorimetry and X-ray diffraction methods

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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

Cited by 12 publications

References 11 publications

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

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

Spectroscopy study of [Ni(NH3)6]X2 compounds. III reorientational correlation times of NH3 and ClO4 groups in [Ni(NH3)6](ClO4)2

Investigation of the phase situation in polycrystalline [Mg(NH3)6](ClO4)2 by adiabatic calorimetry and X-ray diffraction methods

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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

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

Spectroscopy study of [Ni(NH₃)₆]X₂ compounds. III reorientational correlation times of NH₃ and ClO₄ groups in [Ni(NH₃)₆](ClO₄)₂