Editing Hypervalent molecule (section)

== Hypervalent hydrides ==
A special type of hypervalent molecules is hypervalent hydrides. Most known hypervalent molecules contain substituents more electronegative than their central atoms.<ref>{{Cite journal|last1=Reed|first1=Alan E.|last2=Schleyer|first2=Paul v. R.|date=November 1988|title=The anomeric effect with central atoms other than carbon. 2. Strong interactions between nonbonded substituents in mono- and polyfluorinated first- and second-row amines, FnAHmNH2|journal=Inorganic Chemistry|language=en|volume=27|issue=22|pages=3969–3987|doi=10.1021/ic00295a018|issn=0020-1669}}</ref><ref name=":0">{{Cite journal|last1=Pu|first1=Zhifeng|last2=Li|first2=Qian-shu|last3=Xie|first3=Yaoming|last4=Schaefer|first4=Henry F.|date=October 2009|title=Hypervalent molecules, sulfuranes, and persulfuranes: review and studies related to the recent synthesis of the first persulfurane with all substituents carbon-linked|journal=Theoretical Chemistry Accounts|language=en|volume=124|issue=3–4|pages=151–159|doi=10.1007/s00214-009-0621-1|s2cid=96331962|issn=1432-881X}}</ref> Hypervalent hydrides are of special interest because hydrogen is usually less electronegative than the central atom. A number of computational studies have been performed on [[chalcogen hydride]]s<ref name=":0" /><ref>{{Cite journal|last1=Yoshioka|first1=Yasunori|last2=Goddard|first2=John D.|last3=Schaefer|first3=Henry F.|date=February 1981|title=Analytic configuration interaction gradient studies of SH 4, sulfurane|journal=The Journal of Chemical Physics|language=en|volume=74|issue=3|pages=1855–1863|doi=10.1063/1.441275|issn=0021-9606|bibcode=1981JChPh..74.1855Y}}</ref><ref>{{Cite journal|last1=Moc|first1=Jerzy|last2=Dorigo|first2=Andrea E.|last3=Morokuma|first3=Keiji|date=March 1993|title=Transition structures for H2 elimination from XH4 hypervalent species (X = S, Se and Te). Ab initio MO study|journal=Chemical Physics Letters|language=en|volume=204|issue=1–2|pages=65–72|doi=10.1016/0009-2614(93)85606-O|bibcode=1993CPL...204...65M}}</ref><ref>{{Cite journal|last1=Wittkopp|first1=Alexander|last2=Prall|first2=Matthias|last3=Schreiner|first3=Peter R.|last4=Schaefer III|first4=Henry F.|date=2000|title=Is SH4, the simplest 10-S-4 sulfurane, observable?|journal=Physical Chemistry Chemical Physics|volume=2|issue=10|pages=2239–2244|doi=10.1039/b000597p|bibcode=2000PCCP....2.2239W}}</ref><ref>{{Cite journal|last1=Schwenzer|first1=Gretchen M.|last2=Schaefer|first2=Henry F. III|date=March 1975|title=Hypervalent molecules sulfurane (SH4) and persulfurane (SH6)|journal=Journal of the American Chemical Society|language=en|volume=97|issue=6|pages=1393–1397|doi=10.1021/ja00839a019|bibcode=1975JAChS..97.1393S |s2cid=93412551 |issn=0002-7863|url=https://escholarship.org/uc/item/4jg6x11z}}</ref><ref>{{Cite journal|last1=Hinze|first1=Juergen|last2=Friedrich|first2=Oliver|last3=Sundermann|first3=Andreas|date=February 1999|title=A study of some unusual hydrides: BeH2, BeH+6 and SH6|journal=Molecular Physics|language=en|volume=96|issue=4|pages=711–718|doi=10.1080/00268979909483007|issn=0026-8976|bibcode=1999MolPh..96..711H}}</ref> and [[pnictogen hydride]]s.<ref>{{Cite journal|last1=Rauk|first1=Arvi|last2=Allen|first2=Leland C.|last3=Mislow|first3=Kurt|date=May 1972|title=Electronic structure of PH5 and intramolecular ligand exchange in phosphoranes. Model studies|journal=Journal of the American Chemical Society|language=en|volume=94|issue=9|pages=3035–3040|doi=10.1021/ja00764a026|bibcode=1972JAChS..94.3035R |issn=0002-7863}}</ref><ref>{{Cite journal|last1=Kutzelnigg|first1=Werner|last2=Wasilewski|first2=Jan|date=February 1982|title=Theoretical study of the reaction PH<sub>5</sub> → PH<sub>3</sub> + H<sub>2</sub> |journal=Journal of the American Chemical Society|language=en|volume=104|issue=4|pages=953–960|doi=10.1021/ja00368a005|issn=0002-7863}}</ref><ref>{{Cite journal|last1=Wasada|first1=H.|last2=Hirao|first2=K.|date=January 1992|title=Theoretical study of the reactions of pentacoordinated trigonal bipyramidal phosphorus compounds: PH5, PF5, PF4H, PF3H2, PF4CH3, PF3(CH3)2, P(O2C2H4)H3, P(OC3H6)H3, and PO5H4-|journal=Journal of the American Chemical Society|language=en|volume=114|issue=1|pages=16–27|doi=10.1021/ja00027a002|bibcode=1992JAChS.114...16W |issn=0002-7863}}</ref><ref>{{Cite journal|last1=Kolandaivel|first1=P.|last2=Kumaresan|first2=R.|date=August 1995|title=The reaction path of PH5 → PH3 + H2 using an SCF study|journal=Journal of Molecular Structure: THEOCHEM|language=en|volume=337|issue=3|pages=225–229|doi=10.1016/0166-1280(94)04103-Y}}</ref><ref>{{Cite journal|last1=Moc|first1=Jerzy|last2=Morokuma|first2=Keiji|date=November 1995|title=AB Initio Molecular Orbital Study on the Periodic Trends in Structures and Energies of Hypervalent Compounds: Five-Coordinated XH5 Species Containing a Group 5 Central Atom (X = P, As, Sb, and Bi)|journal=Journal of the American Chemical Society|language=en|volume=117|issue=47|pages=11790–11797|doi=10.1021/ja00152a022|bibcode=1995JAChS.11711790M |issn=0002-7863}}</ref> Recently, a new computational study has shown that most hypervalent halogen hydrides XH<sub>n</sub> can exist. It is suggested that IH<sub>3</sub> and IH<sub>5</sub> are stable enough to be observable or, possibly, even isolable.<ref>{{Cite journal|last=Sikalov|first=Alexander A.|date=12 December 2019|title=Hypervalent halogen hydrides HalHn (Hal = Cl, Br, I; n = 3, 5, 7): DFT and ab initio stability prediction|journal=Theoretical Chemistry Accounts|language=en|volume=139|issue=1|pages=8|doi=10.1007/s00214-019-2524-0|s2cid=209331619|issn=1432-2234}}</ref>