A graph‐theoretical study of acyclic polyenes is carried out with an emphasis on the influence of branching on several molecular properties. A definition of branching is given and several branching indices are analyzed. The case of polyenes without a Kekulé structure is discussed briefly. The main conclusions are: (a) thermodynamic stability of conjugated polyenes decreases with branching, but (b) reactivity, in general, increases with branching.

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Part XI: C. F. Wilcox, Jr., I. Gutman, and N. Trinajstić, Tetrahedron (to be published).
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We call “molecular topology” the totality of information contained in the molecular graph.4 If a physical or chemical property of a molecule is largely determined by molecular topology, it is called a “topological property.”
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M. Randić, J. Am. Chem. Soc. (to be published). We thank Dr. Randić for communicating his results prior to publication.
25.
These trees are listed in Ref. 5, Appendix III.
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