Pyramidal inversion: Difference between revisions

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{{Short description|Fluxional scientificprocess equationin trigonal-pyramidal molecules}}

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|[[Image:Amine N-R.svg|96px]]

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| colspan=3 |'''Nitrogen inversion:''' The amine C₃ axis is horizontal; the pair of dots represent the lone pair (on that axis). Note that the the two amine molecules are [[mirror symmetry|symmetric across a mirror plane]]. If the three R groups attached are all unique, then the amine is chiral; isolability depends on the [[Gibbs energy|free energy]] required to invert the molecule.

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In [[chemistry]], '''pyramidal inversion''' (also '''umbrella inversion''') is a [[fluxional molecule|fluxional process]] in compounds with a [[pyramid]]al molecule, such as [[ammonia]] (NH₃) "turns inside out".<ref>{{ cite journal | author1 = Arvi Rauk|author2=[[Leland C. Allen]]|author3=[[Kurt Mislow]] | title = Pyramidal Inversion | journal = [[Angewandte Chemie International Edition]] | year = 1970 | volume = 9 | issue = 6 | pages = 400–414 | doi = 10.1002/anie.197004001}}</ref><ref name="ReferenceA">{{GoldBookRef|file=P04956|title=Pyramidal inversion}}</ref> It is a [[Molecular vibration|rapid oscillation]] of the atom and substituents, the molecule or ion passing through a [[Trigonal planar molecular geometry|planar]] [[transition state]].<ref>{{ cite journal | author = J. M. Lehn | author-link = Jean-Marie Lehn | title = Nitrogen Inversion: Experiment and Theory | journal = Fortschr. Chem. Forsch. | year = 1970 | volume = 15 | pages = 311–377 | doi = 10.1007/BFb0050820}}</ref> For a compound that would otherwise be [[Chirality (chemistry)|chiral]] due to a [[stereocenter]], pyramidal inversion allows its [[enantiomer]]s to [[racemize]]. The general phenomenon of pyramidal inversion applies to many types of molecules, including [[carbanion]]s, [[amines]], [[phosphane|phosphines]], [[arsine]]s, [[stibine]]s, and [[sulfoxide]]s.<ref>{{cite journal |author=Arvi Rauk |author2=Leland C. Allen |author3=Kurt Mislow |year=1970 |title=Pyramidal Inversion |journal=Angewandte Chemie International Edition |volume=9 |issue=6 |pages=400–414 |doi=10.1002/anie.197004001}}</ref><ref name="ReferenceA" />

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==References==

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[[Category:Physical chemistry]]