ORGANIC CHEMISTRY Chapter 14 o When only two substituents are present their relative positions are indicated by the prefixes o-(ortho),m- (meta), and p-(para) or by the use of numbers CH CH CH CH CH 1, 2-Dimethylbenzene 1, 3-Dimethylbenzene 1, 4-Dimethylbenzene O-xylene (m-Xylene) (p-Xylene) ortho meta para 1,2二甲苯 1,3-二甲苯 ,4-二甲苯 邻-二甲苯 间-二甲苯 对-二甲苯 Department of Chemistry, Xiamen UniversityORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 14 When only two substituents are present, their relative positions are indicated by the prefixes o-(ortho), m- (meta), and p-(para) or by the use of numbers. CH3 CH3 CH3 CH3 CH3 CH3 1,2-二甲苯 1,3-二甲苯 1,4-二甲苯 邻-二甲苯 间-二甲苯 对-二甲苯 ( p-Xylene) 1,2-Dimethylbenzene 1,3-Dimethylbenzene 1,4-Dimethylbenzene (o-Xylene) (m-Xylene) ortho meta para