Table 1 The most commonly used topological indices.

Wiener index

D _i,j represents off-diagonal elements of matrix which stands for the shortest distance in term on number of bonds between atom i and j

Valence connectivity index

v _i and v _j are weights (valence delta values) of vertices i and j making up edge in vertex weighted graph G

Balaban index

the average distance sum connectivity; where E is the number of edges, μ is cyclomatic number of G and ds _i is a distance sum

Information-theoretic index

modified Shannon's equation where n is the number of different sets of elements, N _i is the number of elements in the i-th set of elements and the sum is over all sets of elements

Shultz index

molecular topological index (MTI) is based on adjacency matrix (A), the distance matrix (D) and the valency matrix (v); the of elements e _i of the row matrix v [A+D] gives Shultz index