Natural Gas Hydrates: H Structure
Steven Dutch, Professor Emeritus, Natural and Applied Sciences, Universityof Wisconsin - Green BayThe H structure (for Hexagonal) consists of dodecahedra and two additionalsolids. First are 12-sided shapes consisting of squares, hexagons and pentagons(below right). Second are elongated "barrels" consisting of 12pentagons and 8 hexagons (below left). The barrels can fit much largerhydrocarbons than methane.
The 4-5-6 faced solids cluster around the middle band of the barrels.
Below we see how the rear faces of one of the 4-5-6 faced solids connect tothe barrel behind it.
The two shapes form a sheet of 4-5-6 faced polyhedra enclosing barrels.
The dimples in the sheet surrounded by four pentagons are in turn filled bydodecahedra, which enclose hexagonal holes. The holes fit over the barrels inthe sheet below and accept the barrels from the next sheet above.
The oblique view below shows how the sheets stack.
References
Henriet, J.-P., Mienert, J., 1998; Gas hydrates : relevance to world marginstability and climate change, London : The Geological Society, GeologicalSociety special publication no. 137, 338 p.
Kleinberg, Robert; Brewer, Peter, 2001; Probing gas hydrate deposits. American Scientist. vol. 89; no. 3, Pages 244-251.
Holder, Gerald-D (editor); Bishnoi, P. R. (editor), 2000; Gas hydrates;challenges for the future. Annals of the New York Academy of Sciences. 912; NewYork Academy of Sciences. New York, NY, United States. Pages: 1039.
Paull, Charles K. (editor); Dillon, William P. (editor), 2000; Natural gashydrates; occurrence, distribution, and detection. Geophysical Monograph 124,American Geophysical Union. Washington, D.C., United States. Pages: 315.
Haq, Bilal U., 1998; Gas hydrates; greenhouse nightmare? Energy panacea orpipe dream? GSA Today. vol. 8; 11, Pages 1-6. Geological Society of America(GSA). Boulder, CO, United States
Smelik, Eugene A.; King, H. E. Jr., 1997; Crystal-growth studies of naturalgas clathrate hydrates using a pressurized optical cell. American Mineralogist.vol. 82; 1-2, Pages 88-98. Mineralogical Society of America. Washington, DC,United States.
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Created 1 August 2003, Last Update