The following GC base pair is a bonding of two aminos. How does the C and G form a covalent bond shown in the dashed line?

If I apply the octet rule to the oxygen to the left of the dashed line its double bond to carbon achieves 8 in the outer shell. The same for nitrogen to the right of the dashed line, which appears bonding to the carbon.


  • 3
    $\begingroup$ Those aren’t covalent bonds. They’re hydrogen bonds utilizing lone pairs on O and N $\endgroup$
    – Andrew
    Sep 18 at 19:58
  • $\begingroup$ Notice that the hydrogen atoms are also "out of electrons", and that the distance between atoms connected by a dashed line (non-covalent interaction called hydrogen bond) is longer than the distance of atoms connected by a solid line (covalent bond). $\endgroup$
    – Karsten
    Sep 18 at 23:03
  • $\begingroup$ @Nick you need to read up about hydrogen bonds. This is a good start chemguide.co.uk/atoms/bonding/hbond.html $\endgroup$
    – Waylander
    Sep 19 at 11:33
  • $\begingroup$ @Karsten Hydrogen bonds aren't completely non-covalent. Much like halogen bonds, agostic interactions and others, they have some covalent component, being prime reason to even create such categories of bonding. $\endgroup$
    – Mithoron
    Sep 19 at 13:43
  • $\begingroup$ @Mithoron I know, there would be no J-coupling in the NMR without a covalent component. $\endgroup$
    – Karsten
    Sep 20 at 20:00


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