Structure Alkane:single bonds,sp3 carbons Cycloalkane:carbons form a ring ■结构特征 CH3-CH3 ■SP杂化碳原子四面体碳原子 ■o键相连 ■键合原子可绕σ键轴“自由“旋转 1874 J.H.Van't Hoff Utrecht Univ