Flat 6-membered ring with 6 carbons. Each carbon in bonded two 1 hydrogen and 2 other carbons. Because a carbon must always have 4 bonds, there is a delocalised fourth electron on each carbon, which moves around the molecule. This causes all six spare p-orbitals overlap and all six of the delocalised electrons move freely within the overlapping orbitals. The angle between all the bonds is 120 degrees, giving benzene the shape of a hexagon. This has been confirmed by microscopy. The delocalized electron accounts for benzene's stability, addition reactions would break the delocalization and are not energetically favourable, thus it does not readily undergo reactions.