Direct methods in polymer fiber diffraction – the crystal structure of poly(ethylene terephthalate)

Autor:	D. L. Dorset
Rok vydání:	1998
Předmět:	chemistry.chemical_classification Electron density Materials science Polymer Crystal structure Condensed Matter Physics Molecular physics Inorganic Chemistry chemistry Direct methods Phase (matter) Polymer chemistry X-ray crystallography General Materials Science Fiber Fiber diffraction
Zdroj:	Zeitschrift für Kristallographie - Crystalline Materials. 213:445-449
ISSN:	2196-7105 2194-4946
Popis:	Using an x-ray fiber data set from poly(ethylene terephthalate) originally published in 1954, the crystal structure of the polymer was determined by direct methods, via symbolic addition. Of the 68 measured amplitudes, 62 were assigned phase values. Although eight of these terms were incorrectly determined, the ensuing electron density map was a sufficiently well-defined density envelope for fitting the polymer backbone, therefore directly establishing the validity of the earlier determined packing model. On the other hand, visualization of individual atomic positions in the benzene ring was not possible from the electron density map generated from this phase set, even though they would have been found if all phases had been correct.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::b673026991f120ec6d8d20535340e9c2 https://doi.org/10.1524/zkri.1998.213.9.445 Zobrazit plný text záznamu