Editing Ylide (section)

== Resonance structures ==
Many ylides may be depicted by a [[Multiple bond|multiply bonded]] form in a [[resonance structure]], known as the ylene form, while the actual structure lies in between both forms:{{cn|date=December 2019}}
:[[Image:Ph3P=CH2-ylid-phosphorane-resonance-2D.png|260px|Wittig reagent resonance structures]]
The actual bonding picture of these types of ylides is strictly zwitterionic (the structure on the right) with the strong Coulombic attraction between the "onium" atom and the adjacent carbon accounting for the reduced bond length.  Consequently, the carbon anion is trigonal pyramidal.{{Fact|date=February 2021}}