Premium
X‐ray study on the successive phase transition in cholesteryl 2,2,3,3‐tetrafluoropionate (CTFP)
Author(s) -
Nakamura N.,
Yoshimura Y.,
Shimaoka K.,
Yano S.
Publication year - 1984
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889884011067
Subject(s) - phase transition , diffraction , relaxation (psychology) , phase (matter) , crystallography , crystal structure , crystal (programming language) , chemistry , condensed matter physics , atmospheric temperature range , materials science , thermodynamics , optics , physics , organic chemistry , psychology , social psychology , programming language , computer science
These studies on phase transition and crystal structure in a single‐crystal of CTFP by X‐ray diffraction in the temperature range 88 to 293 K show that CTFP undergoes successive phase transitions at about 123, 143 and 178 K and that the existence of another phase transition at about 168 K is possible. In the lowest‐temperature phase, various commensurate and incommensurate structures were found. The appearance of the structure depends on storage duration at 293 K after undergoing the successive phase transitions. The original crystal, just crystallized from acetone solution, showed commensurate structure of which the modulation wave number, δ , is 0.20. The samples stored for a week and a month were both incommensurate. However, the crystals stored for two months were commensurate ( δ = 0.20). Therefore, the storage duration of two months is a relaxation time long enough to recover the genuine structure. In the other temperature phases below 178 K, the crystals were all incommensurate. Consequently, the complicated structural change of CTFP crystals during storage is now well understood as a thermal relaxation phenomenon.