In:
Acta Crystallographica Section B Structural Science, International Union of Crystallography (IUCr), Vol. 61, No. 3 ( 2005-06-01), p. 329-334
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.
Type of Medium:
Online Resource
ISSN:
0108-7681
DOI:
10.1107/S010876810500546X
DOI:
10.1107/S010876810500546X/lc5020sup1.cif
DOI:
10.1107/S010876810500546X/lc5020sup2.rtv
Language:
Unknown
Publisher:
International Union of Crystallography (IUCr)
Publication Date:
2005
detail.hit.zdb_id:
2020841-8
SSG:
13
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