Ionic plastic phases in trimethylammonium trifluoroacetate studied by 1H and 19F NMR spectroscopy, X-ray diffraction and thermal measurements

1H and 19F NMR, differential scanning calorimetric and X-ray powder diffraction measurements were carried out in solid trimethylammonium trifluoroacetate, (CH3)3NHCOOCF3. Two solid–solid phase transitions were observed at 307 and 330 K. The structures of the solid phases obtained above 330 K and between 307 and 330 K are CsCl-type cubic and tetragonal, respectively. In the two phases, both cations and anions perform self-diffusion and isotropic rotation. From the dynamic behaviour of the ions together with thermal data, both phases are assignable as ionic plastic phases.