| | 1 | Author
| Hiroyuki Ishida, Hiroshi Ono, Ryuichi Ikeda | Requires cookie* | | | Title
| Crystal Structure of the High-temperature Solid Phases of Choline Tetrafluoroborate and Iodide  | | | | Abstract
| The crystal structure of the highest-and second highest-temperature solid phases of choline tetrafluoroborate and iodide was determined by X-ray powder diffraction. The structure in the highest-temperature phase of both salts is NaCl-type cubic (a = 10.16(2) Ä, Z = 4 for tetrafluorobo-rate; a = 10.08(2) A, Z = 4 for iodide). The second highest-temperature phase of tetrafluoroborate and iodide is CsCl-type cubic (a = 6.198(6) Ä and Z = 1) and tetragonal (a = 8.706(2) A, c = 6.144(6) Ä, and Z = 2), respectively. DSC was carried out for the iodide, where the presence of three solid-solid phase transitions was confirmed. Enthalpy and entropy changes of these transitions were evaluated. | | | |
Reference
| Z. Naturforsch. 52a, 679—680 (1997); received June 17 1997 | | | |
Published
| 1997 | | | |
Keywords
| Crystal structure, Powder X-ray diffraction, Phase transition | | | |
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| default:Reihe_A/52/ZNA-1997-52a-0679_n.pdf | | | | Identifier
| ZNA-1997-52a-0679_n | | | | Volume
| 52 | |
| 2 | Author
| Hiroyuki Ishida, Masakazu Kato, Hiroshi Ono, Ryuichi Ikeda | Requires cookie* | | | Title
| Cationic Self-diffusion in Solid Choline Perchlorate Studied by NMR | | | | Abstract
| The 1 H spin-lattice and spin-spin relaxation times, and the second moment of the 1 H NMR linewidth of choline Perchlorate, [(Cff^NCfFCHiOHJClC^, were measured in its highest-temperature solid phase, i. e. above 275 K. X-ray powder patterns taken at ca. 380 K revealed that in this phase the crystal has a CsCl-type cubic structure (a = 6.326(4) A and Z = 1). From *H NMR experiments it was found that the cations in this phase undergo isotropic rotation and translational self-diffusion. From the 1 H T, measurements, the activation energies of the cationic rotation and self-diffusion were evaluated to be 21.4 ± 0.4 and 62 ± 3 kJ mol -1 , respectively. | | | |
Reference
| Z. Naturforsch. 52a, 637—639 (1997); received May 28 1997 | | | |
Published
| 1997 | | | |
Keywords
| Ionic plastic phase, Self-diffusion, Crystal structure, Nuclear magnetic resonance | | | |
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| default:Reihe_A/52/ZNA-1997-52a-0637.pdf | | | | Identifier
| ZNA-1997-52a-0637 | | | | Volume
| 52 | |
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