1.4 Lone Pairs

1.4 Lone Pairs

• The first structure is aromatic.
• The second structure is also aromatic.

• Pyrrole has six p electrons, two from the lone pair and two from each of the p bonds.
• The compound is aromatic because the criteria for aromaticity have been satisfied.
• The lone pair is part of the aromatic system.

• The ring would lose its aromaticity.
• The nitrogen atom is uphill in energy and not observed.

• The lone pair is not part of the aromatic system.
• The aromatic system is not being contributed to by 2 hybridized orbitals.

• pyridine is used as a mild base in many reactions.

• Let's look at an example of an aromatic compound.

• For the same reason that pyrrole is aromatic, furan is also aromatic.
• When we are counting to see if we have a Huckel number, we only count one of the lone pairs of the oxygen atom.

• One of the compounds is aromatic.