Journal of Mathematical Chemistry

, Volume 46, Issue 4, pp 1252–1270 | Cite as

On a novel connectivity index

  • Bo ZhouEmail author
  • Nenad Trinajstić
Original Paper


We present a novel connectivity index for (molecular) graphs, called sum-connectivity index and give several basic properties for this index, especially lower and upper bounds in terms of graph (structural) invariants. It appears that this and the original Randić connectivity index that we call product-connectivity index are highly intercorrelated molecular descriptors, the value of the correlation coefficient being 0.991 for trees representing lower alkanes. We determine the unique tree with fixed numbers of vertices and pendant vertices with the minimum value of the sum-connectivity index, and trees with the minimum, second minimum and third minimum, and the maximum, second maximum and third maximum values of this index. Additionally, we discuss the properties of this novel connectivity index for a class of trees representing acyclic hydrocarbons.


Randić connectivity index Sum-connectivity index Product-connectivity index Zagreb indices Molecular graphs Lower and upper bounds 


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Copyright information

© Springer Science+Business Media, LLC 2008

Authors and Affiliations

  1. 1.Department of MathematicsSouth China Normal UniversityGuangzhouChina
  2. 2.The Rugjer Bošković InstituteZagrebCroatia

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