Correct Answer: A cumulene is a hydrocarbon with three or more cumulative double bonds They are analogous to allenes, only having a more extensive chain The simplest molecule in this class is butatriene, which is also called simply cumulene The carbons on the ends are sp² hybridized, with a p-orbital for the 'second' bond in the double bond with their neighboring carbons They have those sp² orbitals overlapping with the s from the hydrogen, and they have a p overlapping in the pi bond with the neighboring carbon They also have a sigma bond with the neighboring carbon I'll get to The middle carbons each have two pi bonds with their neighbors, leaving sp hybridiaztion for the rest So they have sp/sp² with the end carbons, and sp/sp with each other (And they also have p/p in the pi bonds) All orbital overlappings in Cumuene are : * s/sp² * p/p * sp/sp² * sp/sp
