在过渡态理论中,采用传统的对称数有时会给出错误的结果,而采用统计因子l~*和l不能保证总符合微观可逆性原理。本文首次提出活化络合物对称数的正确表达式为,m为活化络合物可区分的构型数,N_i为属于反应物、产物同一分子的在活化络合物中可交换的等价原子数。对于单分子和双分子交换反应,本文的结果与统计因子l的一致,两者结合可成为帮助确定反应机理的行之有效的方法之一。 In the transition state theory, the use of the traditional symmetry number sometimes gives the wrong result, and the use of statistical factors l ~ * and l can not guarantee the total consistent with the principle of microscopic reversibility. In this paper, the exact expression of the symmetric number of activating complex is proposed for the first time, where m is the number of distinguishable configurations of the activating complex, N_i is the exchangeable equivalent atom belonging to the reactant and the same molecule in the activating complex number. For both monomolecular and bimolecular exchange reactions, the results in this paper are consistent with the statistical factor of l, and the combination of the two can be one of the effective methods to help determine the reaction mechanism.