The connecting orbits place most of the electron density between the nuclei of the bound atoms. Antisvyazivayuschie orbitals place most of the electronic density outside the nuclei.
The electrons on the orbital bonds stabilize the molecule, because they are located between the nuclei. They also have lower energies because they are closer to the nuclei. Crossover orbitals place a smaller electron density between the nuclei. Nuclear repulsion is more, so the energy of the molecule increases. Obrashchayuschiesya orbitals are at higher levels of energy than the orbital binds.