Sec 1 Structure Physical Properties Each carbon contributes a p orbital Six p orbitals overlap to give cyclic p system; 合的共轭体系（环状π电子流） Six p electrons delocalized throughout p system高度离域（无单双键之分） High electron density above and below plane of ring平面结构，键角为1200，PlanarSec 1 Structure & Physical Properties Each carbon contributes a p orbital Six p orbitals overlap to give cyclic p system; 闭 合的共轭体系 (环状 电子流 ) Six p electrons delocalized throughout p system 高度离域 (无单双键之分 ) High electron density above and below plane of ring 平面结构，键角为1200 ，Planar