Some bounds for the connectivity index of a chemical graph

Let G be a simple graph. We say that G is a chemical graph if G is connected and the degree d(i) less than or equal to 4 for every vertex i. We consider the connectivity index (1)chi(G) of a chemical graph G. We use some graph theoretic constructions to find bounds for (1)chi X(G) which depend only on the number of vertices, the ramification index, and the cyclomatic number of the graph G. The results are related to the problem of-graph reconstruction from a collection of graph invariants.