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Symmetry properties of chemical graphs. IX. The valence tautomerism in the P 7 3− skeleton
Author(s) -
Randić Milan,
Oakland David O.,
Klein Douglas J.
Publication year - 1986
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.540070106
Subject(s) - tautomer , valence (chemistry) , intramolecular force , graph , molecule , ion , combinatorics , valence bond theory , chemistry , mathematics , crystallography , computational chemistry , physics , stereochemistry , quantum mechanics , molecular orbital
We investigate the intramolecular rearrangement of the P 7 3− ion in which PP bonds are continuously broken and reestablished resulting in a dynamic structure with all seven phosphorus atoms being chemically equivalent. This leads to 7/3 = 1680 valence tautomers. The P 7 3− ion is a typical fluctuating molecule, distantly related to C 10 H 10 bullvalene. In order to determine the symmetry of the process we first consider the problem of the construction of the rearrangement graph. Initial steps toward this goal are illustrated, and additional characterizations of the graph are derived after its construction by computer. A number of properties of this rather complicated graph having 1680 vertices and 2520 edges are discussed: in particular the occurrence of various cycles, the maximal distance between vertices, the count of neighbors at different distance, and finally its symmetry.