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1995 | 88 | 2 | 339-347
Article title

Monotropic Character of Polymorphism in Pentachloropyridine Crystal Studied by Calorimetric and Spectroscopic Methods

Content
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EN
Abstracts
EN
Pentachloropyridine crystals in two polymorphic modifications: tetragonal and monoclinic were studied by differential scanning calorimetry and polarized IR and Raman spectroscopy in 20 to 200 cm^{-1} region and at different temperatures from melting point down to the liquid nitrogen temperature. The 4 K difference in melting points of both forms indicates the occurrence of monotropy. The spectra were discussed in terms of positional disorder in the studied crystals which often happen to be mixtures of the monoclinic crystal and the L- and D-forms of the tetragonal one. The monotropic transition of the metastable tetragonal crystal into the stable monoclinic one was observed in the Raman spectra and under the polarizing microscope at temperatures ranging from 170 to 185 K and as an anomaly on the differential scanning calorymetry diagram at 193 K.
Keywords
EN
Publisher

Year
Volume
88
Issue
2
Pages
339-347
Physical description
Dates
published
1995-08
received
1995-03-13
(unknown)
1995-05-25
Contributors
author
  • Institute of Physical and Theoretical Chemistry, Technical University of Wrocław, Wyb. Wyspiańskiego 27, 50-370 Wrocław, Poland
  • CNRS, Centre de Recherche Paul Pascal, 33-600 Pessac, France
author
  • Group of Condensed Matter and Materials, University of Rennes I, 35-042 Rennes, France
author
  • Laboratory of Dynamics and Structure of Molecular Materials, University of Lille I, 59-655 Villeneuve d'Ascq, France
References
Document Type
Publication order reference
Identifiers
YADDA identifier
bwmeta1.element.bwnjournal-article-appv88z209kz
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