Clathrate hydrate

<p>Clathrate hydrates, or gas hydrates, clathrates, or hydrates, are <a href="/facts/Crystal/e2R2mk3E">crystalline</a> water-based <a href="/facts/Solid/hj5UsXno">solids</a> physically resembling <a href="/facts/Ice/BGvkKFjD">ice</a>, in which small <a href="/facts/Chemical_polarity/KlIJ0zjB">non-polar</a> <a href="/facts/Molecule/N9ljSfFq">molecules</a> (typically <a href="/facts/Gas/hVVAoodV">gases</a>) or <a href="/facts/Chemical_polarity/KlIJ0zjB">polar</a> molecules with large hydrophobic <a href="/facts/Moiety_(chemistry)/WxKqcJe1">moieties</a> are trapped inside "cages" of <a href="/facts/Hydrogen_bond/85V86IIg">hydrogen bonded</a>, frozen <a href="/facts/Water_(molecule)/FFsl65l1">water molecules</a>. In other words, clathrate hydrates are <a href="/facts/Clathrate_compound/QYoBcBg1">clathrate compounds</a> in which the host molecule is <a href="/facts/Water/0lkXnJPK">water</a> and the guest molecule is typically a gas or liquid.  Without the support of the trapped molecules, the <a href="/facts/Crystal_structure/bJ4bCeHd">lattice</a> structure of hydrate clathrates would collapse into conventional ice crystal structure or liquid water. Most low molecular weight gases, including <a href="/facts/Oxygen/acyn6o8r">O</a>2, <a href="/facts/Hydrogen/BoYHjl0J">H</a>2, <a href="/facts/Nitrogen/Nf1QpGDz">N</a>2, <a href="/facts/Carbon_dioxide/xGzpppEp">CO2</a>, <a href="/facts/Methane/kBHneYnh">CH4</a>, <a href="/facts/Hydrogen_sulfide/UbCqjMMk">H2S</a>, <a href="/facts/Argon/QX6NRH6d">Ar</a>, <a href="/facts/Krypton/llkNlCke">Kr</a>, <a href="/facts/Xenon/9E3XR69R">Xe</a>, and <a href="/facts/Chlorine/y27UwYBM">Cl</a>2 as well as some higher <a href="/facts/Hydrocarbon/Dcg95Ju5">hydrocarbons</a> and <a href="/facts/Freon/JkfAjIb9">freons</a>, will form <a href="/facts/Hydrate/dev82l69">hydrates</a> at suitable temperatures and pressures. Clathrate hydrates are not officially chemical compounds, as the enclathrated guest molecules are never bonded to the lattice. The formation and decomposition of clathrate hydrates are <a href="/facts/Phase_transition/eLP2BY8R">first order phase transitions</a>, not chemical reactions. Their detailed formation and decomposition mechanisms on a molecular level are still not well understood.
Clathrate hydrates were first documented in 1810 by <a href="/facts/Sir_Humphry_Davy/aDNRfNou">Sir Humphry Davy</a> who found that water was a primary component of what was earlier thought to be solidified chlorine.
</p><p>Clathrates have been found to occur naturally in large quantities. Around 6.4 trillion (6.4×1012) tonnes of <a href="/facts/Methane/kBHneYnh">methane</a> is trapped in deposits of <a href="/facts/Methane_clathrate/s1USL49e">methane clathrate</a> on the deep <a href="/facts/Ocean_floor/VvxuEWJu">ocean floor</a>. Such deposits can be found on the <a href="/facts/Norwegian_continental_shelf/TubqwGJq">Norwegian continental shelf</a> in the northern headwall flank of the <a href="/facts/Storegga_Slide/pxWhucpE">Storegga Slide</a>. Clathrates can also exist as <a href="/facts/Permafrost/SkFC7LMT">permafrost</a>, as at the <a href="/facts/Mallik_gas_hydrate_site/yHKrmjbM">Mallik gas hydrate site</a> in the <a href="/facts/Mackenzie_River/R5Bzp5QR">Mackenzie Delta</a> of northwestern <a href="/facts/Canadian_Arctic/hQcSoWkW">Canadian Arctic</a>. These natural gas hydrates are seen as a potentially vast energy resource and several countries have dedicated national programs to develop this energy resource. Clathrate hydrate has also been of great interest as technology enabler for many applications like seawater desalination, gas storage, carbon dioxide capture & storage, cooling medium for data centre and district cooling etc. Hydrocarbon clathrates cause problems for the petroleum industry, because they can form inside <a href="/facts/Pipeline_transport/gEmKcFhD">gas pipelines</a>, often resulting in obstructions. Deep sea deposition of <a href="/facts/Carbon_dioxide_clathrate/Gn6cbQ05">carbon dioxide clathrate</a> has been proposed as a method to remove this <a href="/facts/Greenhouse_gas/HXaHqrT8">greenhouse gas</a> from the atmosphere and control <a href="/facts/Climate_change/rEN4BDE7">climate change</a>. Clathrates are suspected to occur in large quantities on some outer <a href="/facts/Planet/rbPjE6Bx">planets</a>, <a href="/facts/Natural_satellite/AE4KQKbq">moons</a> and <a href="/facts/Trans-Neptunian_object/oF5vsbz9">trans-Neptunian objects</a>, binding gas at fairly high temperatures.
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Clathrate hydrate open-in-new

Clathrate hydrate