Raman spectra and structural phase transitions in chain compounds (CH3)4NMnCl3 and (CH3)4NCdCl3

Mlik, Y.; Daoud, A.; Couzi, M.

doi:10.1002/pssa.2210520118

Cited by 26 publications

(34 citation statements)

References 22 publications

(12 reference statements)

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“…1). Our assignment for the low-frequency "external" modes situated a t 0 to 100 cn1-l (Table 3) is only approximate since, as shown for TMMC [8], some coupling occurs between the "rotatory" mode of the chain and the external vibrations of the TMA ion. Such a coupling is even expected to be more pronounced in TrMCC, because of a stronger (NH ... Cl) interaction between the TMA and the CdCI, chain [l].…”

Section: 0 K < T < 2 3 0 Kmentioning

confidence: 78%

“…I n the low-frequency region of the Raman spectrum (0 to 250 cm-l) only lattice vibrations involving the CdCI, chain modes and the "external" vibrations of the TMA are expected [8].…”

Section: Group Theory Of Lattice Dynamics In Chain Compoundsmentioning

confidence: 99%

“…Table 3 Raman-active lattice mode frequencies (in cm-l) observed at 90 Elg not observed ( ? ) chain "breathing" *) From [8].…”

Section: 0 K < T < 2 3 0 Kmentioning

confidence: 99%

“…Tollowing our investigations on chain compounds [8], we have studied the lowfrequency Raman spectra (0 to 300 cm-l) corresponding to the lattice vibrations of TrMCC a t different temperatures ranging from 90 to 423 K. An analysis of these spectra is given, based upon the previously reported structural data I1 to 31.…”

Section: Introductionmentioning

confidence: 99%

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Structural phase transitions in (CH3)3NHCdCl3 studied by low-frequency Raman scattering

Mlik

Daoud

Couzi

1980

Phys. Stat. Sol. (a)

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The low‐frequency Raman spectra (0 to 300 cm−1) of (CH3)3NHCdCl3 single crystal are studied at different temperatures ranging from 90 to 423 K. Between 90 and 342 K, the observed lattice vibrations and polarization selections completely agree with the Pbnm (Z = 4) space‐group previously reported. However, marked spectral changes occurring at 240 to 250 K are assigned to the occurrence of an order‐disorder phase transition. This phase transition does not change the space‐group Pbnm. Transitions at 342 and 374 K are clearly detected: the spectra obtained in these high temperature phases are consistent with the occurrence of complex hexagonal unit‐cells, as determined from X‐ray data by Chapuis et al. The mechanism for this phase sequence is believed to be related to the reorientational dynamics of the (CH3)3NH+ groups, coupled with “rotations” of the CdCl6 octahedra via NH … Cl hydrogen bond interactions.

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Section: 0 K < T < 2 3 0 Kmentioning

confidence: 78%

“…I n the low-frequency region of the Raman spectrum (0 to 250 cm-l) only lattice vibrations involving the CdCI, chain modes and the "external" vibrations of the TMA are expected [8].…”

Section: Group Theory Of Lattice Dynamics In Chain Compoundsmentioning

confidence: 99%

“…Table 3 Raman-active lattice mode frequencies (in cm-l) observed at 90 Elg not observed ( ? ) chain "breathing" *) From [8].…”

Section: 0 K < T < 2 3 0 Kmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Structural phase transitions in (CH3)3NHCdCl3 studied by low-frequency Raman scattering

Mlik

Daoud

Couzi

1980

Phys. Stat. Sol. (a)

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“…A detailed assignment of all the bands is difficult, but we can attribute some of them by comparison with similar compounds[6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. The assignments of the bands observed in the infrared and Raman spectra of [(CH 3 ) 4 N][(C 2 H 5 ) 4 N] ZnCl 4 are listed in…”

mentioning

confidence: 99%

Electrical characterization of the [N(CH3)4][N(C2H5)4]ZnCl4 compound

Karoui

Rhaiem

Guidara

2011

Ionics

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The [N(CH 3 ) 4 ][N(C 2 H 5 ) 4 ]ZnCl 4 compound has been synthesized by a solution-based chemical method. The X-ray diffraction study at room temperature revealed an orthorhombic system with P2 1 2 1 2 space group. The complex impedance has been investigated in the temperature and frequency ranges 420-520 K and 200 Hz-5 MHz, respectively. The grain interior and grain boundary contribution to the electrical response in the material have been identified. Dielectric data were analyzed using the complex electrical modulus M * for the sample at various temperature. The modulus plots can be characterized by full width at half height or in terms of a non-exponential decay function φ(t)=exp[(−t/τ) β ]. The detailed conductivity study indicated that the electrical conduction in the material is a thermally activated process. The variation of the AC conductivity with frequency at different temperatures obeys the Almond and West universal law.

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Raman scattering study of the pressure‐ and temperature‐induced phase transitions in the chain compounds (CH₃)₄NMnCl₃ and (CH₃)₄NCdCl₃

Couzi

Mlik

1986

J Raman Spectroscopy

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The Raman spectra of (CH3),NMnC13 (TMMC) and (CH3),NCdCI3 OMCC) single crystals have been studied at different pressures between 0 and 6 kbar and at temperatures ranging from 80 to 300 K. The P , T phase diagrams of TMMC and TMCC have been determined, and a generalized phase diagram for these systems is proposed. This diagram includes four different structural modificiations whose structures are discussed on the basis of the present Raman results and of previously published structural data. Phase 1 is hexagonal (P6,/m, Z = 2 space group) and exhibits orientational disorder of the (CH3)4Nf groups; phases 11,111 and IV are monoclinic and apparently ordered. Phase 111 (P2,/rn, Z = 2) exhibits a re-entrant character. The Raman spectra of phase I1 are consistent with the P2,/a, 2 = 4 space group induced by anti-phase translations of the octahedra chains, but do not reveal any feature that could be related to an incommensurability. It is concluded that the structure of phase IV is very complex (for instance P2,/rn, Z = 8 or P2,/a, Z = 12). The orderdisorder processes and their possible coupling with other lattice dynamic properties are considered, to explain the 10 I1 and l o 111 transitions; additional structural information is needed in order to choose between the different models examined.

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Raman spectra and structural phase transitions in chain compounds (CH3)4NMnCl3 and (CH3)4NCdCl3

Cited by 26 publications

References 22 publications

Structural phase transitions in (CH3)3NHCdCl3 studied by low-frequency Raman scattering

Structural phase transitions in (CH3)3NHCdCl3 studied by low-frequency Raman scattering

Electrical characterization of the [N(CH3)4][N(C2H5)4]ZnCl4 compound

Raman scattering study of the pressure‐ and temperature‐induced phase transitions in the chain compounds (CH₃)₄NMnCl₃ and (CH₃)₄NCdCl₃

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Raman spectra and structural phase transitions in chain compounds (CH3)4NMnCl3 and (CH3)4NCdCl3

Cited by 26 publications

References 22 publications

Structural phase transitions in (CH3)3NHCdCl3 studied by low-frequency Raman scattering

Structural phase transitions in (CH3)3NHCdCl3 studied by low-frequency Raman scattering

Electrical characterization of the [N(CH3)4][N(C2H5)4]ZnCl4 compound

Raman scattering study of the pressure‐ and temperature‐induced phase transitions in the chain compounds (CH3)4NMnCl3 and (CH3)4NCdCl3

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Raman scattering study of the pressure‐ and temperature‐induced phase transitions in the chain compounds (CH₃)₄NMnCl₃ and (CH₃)₄NCdCl₃