double bond
Recall that a double bond consists of one sigma bond and one pi bond. In order for a double bond to be formed, each participating carbon atom must have at least one unhybridized p orbital. In a carbon-carbon double bond where both carbons are bonded to two additional atoms, each carbon is sp 2 hybridized. The double bond includes a sigma bond between a hybrid orbital from each carbon and a pi bond between the leftover p orbital from each carbon. The angles between any two bonds for an sp 2 hybridized carbon are approximately 120.