Experimental evidence indicates that the three bonds in a carbon radical have trigonal planar geometry, and therefore the carbon is considered to be sp 2 -hybridized with the unpaired electron occupyi...Experimental evidence indicates that the three bonds in a carbon radical have trigonal planar geometry, and therefore the carbon is considered to be sp 2 -hybridized with the unpaired electron occupying the perpendicular, unhybridized 2p z orbital. A higher energy state, in which the two highest energy electrons are paired in the same π* 2p orbital, is called the singlet state of oxygen.
