Topological representations for the intramolecular isomerizations of octahedral complexes are given. The number of dimensions which have to be used for this description depends on the complexity of the chemical system and becomes too great for some of the most general cases to be useful in practice. Therefore, another model is given, where the chemical transformations are represented by permutations of structures located at the edges of triangular faces of a hypertetrahedron. © 1969 Springer-Verlag.