Oxocarbenium
In organic chemistry, an oxocarbenium ion (alternatively spelled oxacarbenium) is a chemical species characterized by a central sp2-hybridized atom of carbon, a substituent atom of oxygen, and an overall positive charge that is delocalized between the central carbon and oxygen atoms (R2[CO]+R). An oxocarbenium ion is represented by two limiting resonance structures, one in the form of a carbenium ion with the positive charge on carbon (>C+−O−) and the other in the form of an oxonium species with the formal charge on oxygen (>C=O+−).