提出了反应分子的几何特征和化学性质的拓扑指数Ｆ３，建立了孤立原子的电负性标度Ｉｔ，并用Ｆ３研究了一些有机化合物的标准生成焓ΔｆＨφｍ、沸点、密度、折光率等性质．结果表明，Ｆ１／６３与ΔｆＨφｍ呈线性关系．拓扑电负性Ｉｔ不依赖于实验数值，物理意义明确，和鲍林电负性的相关系数达到０．９７５９．用包含Ｉｔ的Ｆ３研究卤代烃的沸点、密度、折光率比用Ｉ构成的Ｆ３的结果更好 The topological index F3 of the geometrical and chemical properties of the reaction molecule is proposed. The electronegativity scale It of isolated atoms is established. The standard enthalpy of formation ΔfHφm, boiling point, density and refractive index of some organic compounds are also studied by using F3. The results showed that there was a linear relationship between F1 / 63 and ΔfHφm. Topological electronegativity It does not depend on the experimental values, the physical meaning is clear, and Pauling electronegativity correlation coefficient of 0.9759. It is better to study the boiling point, density and refractive index of halogenated hydrocarbons with F3 which contains It than the result of F3 with I