ABSTRACT
Simple submechanisms are minimum balanced structural units underlying the structure of reaction networks. Therefore, the classification of reaction mechanisms can be based on the classification of simple submechanisms. The reaction mechanism structure directly answers the question of whether the reaction is a chain one or not. Balanced and partially balanced mechanisms can be classified in terms of the submechanism graphs. Sometimes the structure of the submechanism graph correlates with commonly accepted concepts, which are widely accepted by chemists. Surprisingly, the graph-theoretical analysis revealed that nonbranched and branched chain mechanisms are structurally distinct cases. Reaction mechanisms contain two simple submechanisms, which have a common subgraph consisting of only one vertex. The use of bipartite graphs provides a stronger basis for the classification of these systems because nonlinearity of a mechanism is one of the key features of the polyfunctionality. In all cases, the submechanism graph determines the structure of the mechanism better than commonly accepted terms in mechanistic chemistry.
