提出了一个计算不饱和烃分子中碳原子价点价δ i 的新方法 ,以δ i 为核心建构了分子价连接性指数 mX (m =0 ,1 ) ,并研究了烷基苯标准生成焓与 mX 指数的相关性。结果表明 ,mX 指数对烷基苯的结构选择性和性质相关性均优于 mXv 指数和F′指数。以0 X 、1X 和碳原子数N为自变量的三元线性回归方程为 :-ΔfHm =3 8 0 790 X +5 .0 91 1X +95 4 .991N-1 5 0 1 .63 9,该方程对烷基苯标准生成焓的预测结果相当准确 A new method to calculate the valence valence δ i of carbon atoms in unsaturated hydrocarbon was proposed. The molecular valence connectivity index mX (m = 0, 1) was constructed with δ i as the core. The standard enthalpy of formation of alkylbenzene Correlation with mX index. The results showed that both the mXv index and the F ’index of mX index were better than those of mXv. The ternary linear regression equation with 0 X, 1X and carbon number N as independent variables is: -ΔfHm = 3 8 0 790 X +5 .0 91 1X +95 4 .991N -1 5 0 1 .63 9 , The equation predicts the standard enthalpy of formation of alkylbenzene quite accurately