2. cis. trans-isomers 由于双键不能自由旋转而造成的 CH3 CH3 CH3 H H CH3 trans p 3.5 0.9°C p 889」2. cis, trans-isomers: 由于双键不能自由旋转而造成的 C = C CH3 H H CH3 C = C CH3 CH3 H H cis trans b.p. 3.5 0.9°C m.p. -139.5 -105.5 d. 0.6213 0.6242