Phase transitions motions in solid trimethylethylammonium iodide studied by1H and127I NMR conductivity, X-ray diffraction, and thermal analysis

Hiroyuki Ishida, Yoshihiro Furukawa, Setsuo Kashino, Setsuko Sato, Ryuichi Ikeda

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38 Citations (Scopus)


H and 127 I NMR, differential thermal analysis (DTA), differential scanning calorirnetry (DSC), electrical conductivity, and powder and single crystal X-ray diffractions were studied for trimethylethylammonium iodide. Three solid phases, named I, II, and III, were obtained above 410 K, between 336 and 410 K, and below 336 K, respectively. Powder X-ray patterns showed that Phase I and II have a NaCl-type cubic structure (a = 10.00(1) Å, Z = 4) and a tetragonal structure (a = 8.430(5), c = 6.216(4) Å, Z = 2), respectively. The structure of Phase III was determined to be orthorhorabic (Pnam (#62), a = 11.294(4), b = 10.729(2), c = 7.158(6) Å, Z = 4) by single crystal X-ray diffraction. In Phase III, the C3, reorientation of CH3, groups and the C3′ reorientation of the whole (CH3)3N group in the cation were observed by 1H NMR. In Phase II, the cation is expected to perform the quasi-isotropic reorientation. In Phase I, the cation was found to carry out the isotropic reorientation, while the spherical anion the translational self-diffusion, as evidenced by 1H and 127I NMR, and electrical conductivity. Phase II and I are, therefore, dynamically disordered phases; especially, Phase I is highly disordered. From the dynamical behaviour of the cation and anion, and thermal properties, Phase I can be classified into an ionic plastic phase with a Nad-type structure.

Original languageEnglish
Pages (from-to)433-439
Number of pages7
JournalBerichte der Bunsengesellschaft/Physical Chemistry Chemical Physics
Issue number4
Publication statusPublished - Dec 1 1996


  • Crystal structure
  • Nuclear magnetic resonance
  • Phase transitions
  • Spectroscopy

ASJC Scopus subject areas

  • Chemical Engineering(all)


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