Oxygen in Organic Compounds

Oxygen can form many types of compounds with carbon. The possibilities using only carbon and hydrogen are somewhat limited, but things quickly get a lot more complex and interesting with oxygen included.

Oxygen has two bonds in organic compounds.

  • This is because oxygen has 6 valence electrons, so it’s missing two for its full set of 8 valence electrons. Oxygen forms two covalent bonds (shared electron pairs) to get 8 electrons.
  • Reminder: C has four bonds and H has one bond

Functional Group: a group of atoms that gives an organic molecule a specific set of properties.

Oxygen can form a variety of functional groups when it combines in certain ways with carbon and hydrogen.

Alcohol \chemfig{[,.4]-C(-[2])(-[6])-[,.5]OH}
Acid \chemfig{[,0.6]-[,.4]C(=[6]O)-OH}
Ether \chemfig{[,0.6]-[,.4]C(-[2,.4])(-[6,.4])-O-C(-[2,.4])(-[6,.4])-[,.4]}
Ester \chemfig{[,0.6]-[,.4]C(-[2,.4])(-[6,.4])-O-C(=[6,.6]O)-[,.4]}
Aldehyde \chemfig{[,0.6]-[,.4]C(=[6]O)-H}
Ketone \chemfig{[,0.6]-[,.4]C(-[2,.4])(-[6,.4])-C(=[6]O)-C(-[2,.4])(-[6,.4])-[,.4]}

 

A line is usually not drawn to show a bond between O and H, but the bond is still there.

\chemfig{[,.4]-C(-[2])(-[6])-[,.6]C(-[2])(-[6])-[,.6]O-[,.6]H}

is the same as

\chemfig{[,.4]-C(-[2])(-[6])-[,.6]C(-[2])(-[6])-[,.6]OH}

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