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The High‐Pressure Effect on the Phase Transition in Pyridinium Hexafluorophosphate
Author(s) -
Szafraniak I.,
Czarnecki P.,
Mayr P.U.,
Dollhopf W.
Publication year - 1999
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/(sici)1521-3951(199905)213:1<15::aid-pssb15>3.0.co;2-8
Subject(s) - hexafluorophosphate , pyridinium , phase transition , hydrostatic pressure , chemistry , enthalpy , thermodynamics , materials science , ionic liquid , organic chemistry , physics , catalysis
The effect of hydrostatic pressure on the phase transition in pyridinium hexafluorophosphate was studied by the methods of pressure dilatometry, pressure dielectric spectroscopy and DSC. The nonlinear increase of the phase transition temperature with increasing pressure was analysed. The phase transition was established as the order–disorder type and the change in entropy at this transition was related to the change in inequivalent positions of the pyridinium cation. The change in the activation enthalpy under the effect of pressure was derived and related to an increase in reorientation barrier heights.