Such reactions, in which the π bond of an alkene reacts to form two new σ bonds, are energetically favourable because the new bonds formed (two carbon-hydrogen σ bonds) are stronger than the bonds broken (one carbon-carbon π bond and one hydrogen-hydrogen σ bond).
Due to different bond enthalpies of Si-O (799.6 kJ/mol), O-O (498.4 kJ/mol), N-N (945.3 kJ/mol), and Si-N (470 kJ/mol), the formation of Si-O and N-N bonds are energetically favorable during sputtering of the SiON target in an oxygen ambient.
Furthermore, there is a synergistic effect between the presence of phosphorus and subsequent heat treatment, as phosphorus actively promotes the dealumination of zeolites during thermal treatment, which indicates that the formation of Al O P bonds is energetically favoured.
Calculations by Zimmerman and co-workers suggested that heterolysis of the C O bond is energetically preferred over the homolysis, especially in the presence of ortho and meta substituents stabilizing the cation.
Therefore, the process of adding hydrogen to acetylene and ethylene in an exothermic process which releases energy due to the replacement of the pi bond by the energetically lower sigma bond in ethane.
With the aid of these results, the elastic properties of a perfectly bonded spherical particle energetically equivalent to an imperfectly bonded one in an infinite matrix are determined.
In other words, the relative inter-tube sliding in such a bridged MWCNT involves breaking the covalent C-C bridging bonds, thus is energetically unfavorable.
Therefore, this reaction is exothermic, as it replaces pi bonds by the energetically more stable sigma bonds.
In the thermally stable mutants, the L94L S95L peptide bond adopts an energetically unfavorable non-X-proline cis conformation, but the overall CDR-L3 loop converted to CS1.
Thus, the conformation with the disturbed π-conjugated bond system became energetically favorable.
