The electronegativity ( x L) and atomic potential ( Z*/r c) of Lewis acids are primary factors to affect hard soft scale ( F A).
Ｌｅｗｉｓ酸的电负性（ｘＬ）和原子势（Ｚ／ｒｃ）是影响Ｌｅｗｉｓ酸硬软度（ＦＡ）的主要因素，本文给出了它们之间的数学关系式。
The synthetic explanation of nucleophiticity of diagent and catalyst selection in substitution reaction is discussed according to hard-soft acid-base theory Electrphitic reaction center of multifunctional group is determined.
从硬软酸碱理论出发对两可试剂的亲核性，取代反应中催化剂的选择性进行了综合的解释，指出了多官能团亲电反应中心，通过实例证明了离子型反应的选择性规律。
