Editing Halogen (section)

== Superhalogen ==
{{Main|Superatom}}
Certain aluminium clusters have superatom properties. These aluminium clusters are generated as anions ({{math|Al{{su|b=''n''|p=−}}}} with ''n'' = 1, 2, 3, ... ) in helium gas and reacted with a gas containing iodine. When analyzed by mass spectrometry one main reaction product turns out to be {{math|{{chem|Al|13|I|−}}}}.<ref name="bergeron/2004">{{cite journal | doi =  10.1126/science.1093902| pmid =  15066775| title =  Formation of Al<sub>13</sub>I<sup>−</sup>: Evidence for the Superhalogen Character of Al<sub>13</sub>| journal =  Science| volume =  304| issue =  5667| pages =  84–7| year =  2004| last1 =  Bergeron| first1 =  D. E.| last2 =  Castleman| first2 =  A. Welford| last3 =  Morisato| first3 =  Tsuguo| last4 =  Khanna| first4 =  Shiv N.| bibcode =  2004Sci...304...84B| s2cid = 26728239}}</ref> These clusters of 13 aluminium atoms with an extra electron added do not appear to react with oxygen when it is introduced in the same gas stream. Assuming each atom liberates its 3 valence electrons, this means 40 electrons are present, which is one of the magic numbers for sodium and implies that these numbers are a reflection of the noble gases.

Calculations show that the additional electron is located in the aluminium cluster at the location directly opposite from the iodine atom. The cluster must therefore have a higher electron affinity for the electron than iodine and therefore the aluminium cluster is called a superhalogen (i.e., the vertical electron detachment energies of the moieties that make up the negative ions are larger than those of any halogen atom).<ref>{{Cite journal|title = Superhalogens as Building Blocks of Halogen-Free Electrolytes in Lithium-Ion Batteries†|journal = Angewandte Chemie|volume = 126|issue = 50|pages = 14136|doi = 10.1002/ange.201408648|year = 2014|last1 = Giri|first1 = Santanab|last2 = Behera|first2 = Swayamprabha|last3 = Jena|first3 = Puru| bibcode=2014AngCh.12614136G }}</ref> The cluster component in the {{math|{{chem|Al|13|I|-}}}} ion is similar to an iodide ion or a bromide ion. The related {{math|{{chem|Al|13|I|2|-}}}} cluster is expected to behave chemically like the [[triiodide]] ion.<ref name="ball">{{cite journal | first =Philip | last = Ball| title =A New Kind of Alchemy| journal =New Scientist | date = 16 April 2005}}</ref><ref name="bergeron/2005">{{cite journal | doi =10.1126/science.1105820| pmid =15653497| title =Al Cluster Superatoms as Halogens in Polyhalides and as Alkaline Earths in Iodide Salts| journal =Science| volume =307| issue =5707| pages =231–5| year =2005| last1 =Bergeron| first1 =D. E.| last2 =Roach| first2 =P. J.| last3 =Castleman| first3 =A. W.| last4 =Jones| first4 =N. O.| last5 =Khanna| first5 =S. N.| bibcode =2005Sci...307..231B| s2cid =8003390}}</ref>