text: Outside of the industrial sector, cracking of C-C and C-H bonds are rare chemical reactions.  In principle, ethane can undergo homolysis:
  :CHCH → 2 CH•
  Because C-C bond energy is so high (377 kJ/mol), this reaction is not observed under laboratory conditions.  More common examples of cracking reactions involve retro-Diels-Alder reactions.  Illustrative is the thermal cracking of dicyclopentadiene to produce cyclopentadiene.