Bounds for the Randic connectivity index

For a saturated hydrocarbon with n carbon atoms and m carbon-carbon bonds and with Randic connectivity index chi, two functions, L = L(n,m) and U = U(n,m), are determined, such that L < or = chi < U. These bounds are better than those previously reported; for most chemically relevant values of n and m there exist hydrocarbons for which chi = L or chi = U.