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Phase Transition of a Structure II Cubic Clathrate Hydrate to a Tetragonal Form
Author(s) -
Takeya Satoshi,
Fujihisa Hiroshi,
Yamawaki Hiroshi,
Gotoh Yoshito,
Ohmura Ryo,
Alavi Saman,
Ripmeester John A.
Publication year - 2016
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201602733
Subject(s) - clathrate hydrate , hydrate , tetragonal crystal system , crystallography , crystal structure , chemistry , phase transition , phase (matter) , methane , materials science , thermodynamics , organic chemistry , physics
Abstract The crystal structure and phase transition of cubic structure II (sII) binary clathrate hydrates of methane (CH 4 ) and propanol are reported from powder X‐ray diffraction measurements. The deformation of host water cages at the cubic–tetragonal phase transition of 2‐propanol+CH 4 hydrate, but not 1‐propanol+CH 4 hydrate, was observed below about 110 K. It is shown that the deformation of the host water cages of 2‐propanol+CH 4 hydrate can be explained by the restriction of the motion of 2‐propanol within the 5 12 6 4 host water cages. This result provides a low‐temperature structure due to a temperature‐induced symmetry‐lowering transition of clathrate hydrate. This is the first example of a cubic structure of the common clathrate hydrate families at a fixed composition.