Abstract: the paper contains material on the current state of the problem of the orientation of exchange reactions in triple and more complex reciprocal systems in the absence of a solvent. It provides an analytical overview of the state of the problem from its inception to the end of the twentieth century, in which a critical analysis of all methods of solving it has been made for this period. As a result of numerous studies, various criteria were proposed for assessing the direction of processes in these systems, which, unfortunately, are characterized by a number of shortcomings. As a result, by the present time the problem of choosing the optimal criterion for directionality of exchange reactions in mutual systems in the absence of a solvent remains practically unresolved. The testing of the last was carried out on 53 triple mutual systems of various types for the purpose of falling out on their share of positive solutions to problems. Based on the analysis of the results obtained in this case, preference is given to the rules of Gustavson and the authors of the present work, the formulations of which are given in the text of the article.
Keywords: directivity of exchange reactions, triple and more complex reciprocal systems, Gustavson