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Transformations in methane hydrates

Proceedings of the National Academy of Sciences of the United States of America

By:
, , , , , , , ,
DOI: 10.1073/pnas.250466497

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Abstract

Detailed study of pure methane hydrate in a diamond cell with in situ optical, Raman, and x-ray microprobe techniques reveals two previously unknown structures, structure II and structure H, at high pressures. The structure II methane hydrate at 250 MPa has a cubic unit cell of a = 17.158(2) A?? and volume V = 5051.3(13) A??3; structure H at 600 MPa has a hexagonal unit cell of a = 11.980(2) A??, c = 9.992(3) A??, and V = 1241.9(5) A??3. The compositions of these two investigated phases are still not known. With the effects of pressure and the presence of other gases in the structure, the structure II phase is likely to dominate over the known structure I methane hydrate within deep hydrate-bearing sediments underlying continental margins.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Transformations in methane hydrates
Series title:
Proceedings of the National Academy of Sciences of the United States of America
DOI:
10.1073/pnas.250466497
Volume
97
Issue:
25
Year Published:
2000
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Proceedings of the National Academy of Sciences of the United States of America
First page:
13484
Last page:
13487
Number of Pages:
4