Hydrated methane

Since methane is almost always a byproduct of organic decay, it is not surprising that vast potential reserves of methane have been found trapped in ocean floor sediments. Methane forms continually by tiny bacteria breaking down the remains of sea life. In the early 197Qs it was discovered that this methane can dissolve under the enormous pressure and cold temperatures found at the ocean bottom. It becomes locked in a cage of water molecules to form a methane hydrate (methane weakly combined chemically with water). This "stored" methane is a resource often extending hundreds of meters down from the sea floor. 

P. M. Rodger, T. R. Forester, and W. Smith. Simulations of the methane hydrate/methane gas interface near hydrate forming conditions. Fluid Phase Equilibria, 116(l-2) 326—332, 1995. 

As has been proposed by numerous studies (e.g., Rohl et al. 2000 Dickens 2003) the massive release of gas hydrates could modify climate. The best example for this hypothesis are sedimentary rocks deposited at around 55 Ma during the Paleocene-Eocene thermal maximum, where a decrease of 2-3%c in carbonate-carbon is interpreted as a consequence of an abrupt thermal release of gas-hydrate methane and its subsequent incorporation into the carbonate pool. 

In xenon hydrate, methane hydrate, and other hydrates involving small molecules the eight polyhedron centers per unit cube are occupied by the xenon or methane molecules, their composition accordingly being Xe-5JH 0 and CHi-SjHiO. 

As simple hydrates, methane, and hydrogen sulfide can stabilize the 512 cavities of structure I (size ratios of 0.86 and 0.90, respectively) and they can occupy all the large 51262 cavities of si (size ratios of 0.74 and 0.78, respectively). Ethane occupies the 51262 cavities of structure I with a ratio of 0.94. Propane and iso-butane each occupy the 51264 cavities of structure II with a size ratio of 0.94 and 0.98, respectively. 

Hydrate Methane at high pressure Reference Dyadin and Aladko (1996) ... 

Hydrate Methane at High Pressure Reference Nakano et al. (1999) Phases Lw-H-V... 

Hydrate Methane + ethane Reference Deaton and Frost (1946)... 

Hydrate Methane + ethane Reference Holder and Grigoriou (1980) Phases L y-H-V... 

Hydrate Methane + propane Reference Verma et al. (1974) Phases Lw-H-V and Lw-H-V-Lhc... 

Hydrate Methane + propane Reference Song and Kobayashi (1982)... 

Hydrate Methane + n-butane Reference John and Holder (1982b)... 

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