text: A parallel relationship can easily be drawn between halogen bonding and hydrogen bonding. Both interactions revolve around an electron donor/electron acceptor relationship, between a halogen-like atom and an electron-dense one.  But halogen bonding is both much stronger and more sensitive to direction than hydrogen bonding.  A typical hydrogen bond has energy of formation ; known halogen bond energies range from 10–200 kJ/mol.
  The σ-hole concept readily extends to pnictogen, chalcogen and aerogen bonds, corresponding to atoms of Groups 15, 16 and 18 (respectively).