Editing Clathrate compound (section)

== Examples ==
[[File:Xenon-paraquinol (JAMKEN) clathrate.png|thumb|Portion of the lattice of the clathrate xenon-paraquinol.<ref>{{cite journal |doi=10.1107/S0108270188014556|title=Β-Hydroquinone xenon clathrate|year=1989|last1=Birchall|first1=T.|last2=Frampton|first2=C. S.|last3=Schrobilgen|first3=G. J.|last4=Valsdóttir|first4=J.|journal=Acta Crystallographica Section C Crystal Structure Communications|volume=45|issue=6|pages=944–946|bibcode=1989AcCrC..45..944B }}</ref>]]Clathrates have been explored for many applications including: gas storage, gas production, gas separation, [[desalination]], [[Thermoelectric materials|thermoelectrics]], [[photovoltaics]], and batteries.
* Clathrate compounds with formula ''A''<sub>8</sub>''B''<sub>16</sub>''X''<sub>30</sub>, where ''A'' is an [[alkaline earth metal]], ''B'' is a [[Boron group|group III]] element, and ''X'' is an element from [[Carbon group|group IV]] have been explored for thermoelectric devices. Thermoelectric materials follow a design strategy called the ''phonon glass electron crystal'' concept.<ref>{{Cite journal |last1=Nolas |first1=G. S. |last2=Cohn |first2=J. L. |last3=Slack |first3=G. A. |last4=Schujman |first4=S. B. |date=1998-07-13 |title=Semiconducting Ge clathrates: Promising candidates for thermoelectric applications |journal=Applied Physics Letters |language=en |volume=73 |issue=2 |pages=178–180 |doi=10.1063/1.121747 |bibcode=1998ApPhL..73..178N |issn=0003-6951|doi-access=free }}</ref><ref>{{cite journal | vauthors=((Beekman, M.)), ((Morelli, D. T.)), ((Nolas, G. S.)) | journal=Nature Materials | title=Better thermoelectrics through glass-like crystals | volume=14 | issue=12 | pages=1182–1185 | date=2015 | issn=1476-4660 | doi=10.1038/nmat4461| pmid=26585077 | bibcode=2015NatMa..14.1182B }}</ref> Low [[thermal conductivity]] and high electrical conductivity is desired to produce the [[Thermoelectric effect|Seebeck Effect]]. When the guest and host framework are appropriately tuned, clathrates can exhibit low thermal conductivity, i.e., ''phonon glass'' behavior, while electrical conductivity through the host framework is undisturbed allowing clathrates to exhibit ''electron crystal''. 
* [[Methane clathrate]]s feature the hydrogen-bonded framework contributed by water and the guest molecules of methane.  Large amounts of [[methane]] naturally frozen in this form exist both in [[permafrost]] formations and under the ocean sea-bed.<ref>{{cite news|issue = 2714|url-status = dead|url = https://www.newscientist.com/article/mg20227141-100-ice-on-fire-the-next-fossil-fuel/|title = Ice on fire: The next fossil fuel|last = Pearce|first = Fred|date = 27 June 2009|work = [[New Scientist]]|pages = 30–33|accessdate = July 5, 2009|archive-date = April 13, 2016|archive-url = https://web.archive.org/web/20160413101737/https://www.newscientist.com/article/mg20227141-100-ice-on-fire-the-next-fossil-fuel/}}</ref> Other hydrogen-bonded networks are derived from [[hydroquinone]], [[urea]], and [[thiourea]].  A much studied host molecule is [[Dianin's compound]].
[[File:Cd(CN)2CCl4.jpg|thumb|Cd(CN)<sub>2</sub>&middot;CCl<sub>4</sub>: [[Cadmium cyanide]] clathrate framework (in blue) containing [[carbon tetrachloride]] (C atoms in gray and disordered Cl positions in green) as [[Host–guest chemistry|guest]].]]
* [[Hofmann clathrates]] are [[coordination polymer]]s with the formula Ni(CN)<sub>4</sub>·Ni(NH<sub>3</sub>)<sub>2</sub>(arene).  These materials crystallize with small aromatic guests (benzene, certain xylenes), and this selectivity has been exploited commercially for the separation of these hydrocarbons.<ref name=Ullmann/> [[Metal organic framework]]s (MOFs) form clathrates.
[[File:IRMOF-1 wiki.png|thumb|[[MOF-5]], an example of a [[metal organic framework]]: the yellow sphere represents the guest cavity.]]