Connectivity Index HD

Construction of the generalized connectivity index x(HD) for 3,4-dimethylheptane is illustrated in Table 9.2 at left. After making a list of bonds (the first column of 

List of Bonds and Bond Contribution to the Connectivity Index x(HD) for 3,4-Dimethylheptane and 3-Ethyl-2-Methylhexane 

The x(HD) for the two nonane isomers are obtained by summing bond contributions and are listed in the last row of Table 9.2. As one can see, the x(HD) are very similar, differing by less then 1%, which suggess that the x(HD) index may be a suitable measure of molecular similarity. Based on the x(HD) index, the two most similar pairs among the 11 pairs of nonane isomers are 3,4-dimethylheptane and 3-ethyl-2-methylhexane. This can be seen from the last column in Table 9.3, in which 

The Relative Similarity of a Selection of More Similar Nonane Isomers Based on the Difference in Their x(HD) Values 

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