Ice-like structure of water

Figure 3. Model for a hydronium ion inner layer on the Pt(lll) surface derived from the long-period ice-like structures of water on metals at low temperature.

There are also large reservoirs of CH4 stored as methane clathrate methane hydrate), a crystalline ice-like structure of water and CH4 that can exist at high pressures and low temperatures, such as may occur in areas of permafrost and beneath certain ocean sediments. Figure 4.51 shows the stability diagram of methane clathrate. Approximately 2 X10 Tg CH4 are estimated to be stored as methane clathrate in the ocean floor (Archer et al., 2009). 

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