- Phosphorane
A phosphorane is a
functional group inchemistry withpentavalent phosphorus . It has the general structure PR5. The parent compound is the non-stable phosphoran PH5 or λ5-Phosphan (lambda5phosphan) according toIUPAC nomenclature . In the same vein Pentaphenylphosphoran Ph5P is properly named Pentaphenyl-λ5-Phosphan.Phosphoranes adopt a
trigonal bipyramidal molecular geometry with the two apical bonds longer than the three equatorial bonds. The accepted view for thechemical bond ing taking place is that of a rehybridization in phosphorus of sp³ orbitals with a dz² to a new sp³p orbital. The dz² is considered very energetic and alternative theories attempt to explain this type of bonding better. In athree-center four-electron bond model tworesonance structure s along the apical bonds are X-...P+-X and X-P+...X- Ref|Quin.Phosphoranes of the type R3P=CR2 with a phosphorus carbon double bond or
ylide arereagent s in theWittig reaction , for instance methylenetriphenylphosphorane or Ph3P=CH2.Other phosphorus compounds are
trivalent phosphine s andtetravalent phosphonium salts.See also
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Organophosphorus chemistry References
# "A Guide to Organophosphorus Chemistry" Louis D. Quin 2000 John Wiley & Sons ISBN 0-471-31824-8
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