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Ab initio structure determination of the high-temperature phase of anhydrous caffeine by X-ray powder diffraction.
| Content Provider | Semantic Scholar |
|---|---|
| Author | Derollez, Patrick Correia, Natália T. Danéde, Florence Capet, Frédéric Affouard, Frédéric Lefèbvre, Jacques Descamps, Marc |
| Copyright Year | 2005 |
| Abstract | The high-temperature phase I of anhydrous caffeine was obtained by heating and annealing the purified commercial form II at 450 K. This phase I can be maintained at low temperature in a metastable state. A powder X-ray diffraction pattern was recorded at 278 K with a laboratory diffractometer equipped with an INEL curved position-sensitive detector CPS120. Phase I is dynamically orientationally disordered (the so-called plastic phase). The Rietveld refinements were achieved with rigid-body constraints. It was assumed that on each site, a molecule can adopt three preferential orientations with equal occupation probability. Under a deep undercooling of phase I, below 250 K, the metastable state enters in a glassy crystal state. |
| File Format | PDF HTM / HTML |
| DOI | 10.1107/S010876810500546X |
| PubMed reference number | 15914898 |
| Journal | Medline |
| Volume Number | 61 |
| Part | 3 |
| Alternate Webpage(s) | http://journals.iucr.org/b/issues/2005/03/00/lc5020/lc5020.pdf |
| Alternate Webpage(s) | https://doi.org/10.1107/S010876810500546X |
| Journal | Acta crystallographica. Section B, Structural science |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
