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The short answer for why benzene rings are common is aromaticity, which makes it a very stable structure. Rings with fewer than 6 members are uncommon in chemis
by mtdewcmu 13y ago
The short answer for why benzene rings are common is aromaticity, which makes it a very stable structure. Rings with fewer than 6 members are uncommon in chemistry, because the angles are not what the bonds naturally want to be and so they are increasingly unstable.
As for nature in general, you could probably come up with a convincing argument that boils down to: 6 is a nice round number. It has 2 and 3 as factors.
- Komodo9 13y ago>Rings with fewer than 6 members are uncommon in chemistry In chemistry, or in nature? five membered rings show up all over the place, both aromatic and otherwise. Granted, cyclobutyl (4 member, square) and cyclopropyl (3 membered, triangle) suffer from ring strain and are uncommon, but 5, 6, 7, (or higher) rings show up all over the place. Examples off the top of my head are the cyclopentadienyl ion pervasive in inorganic chemistry (see ferrocene, et al) and amino acids tryptophan, tyrosine, histidine, and phynylalanine all feature cyclic aromatics 5 and 6 membered, as well as proline with a non-aromatic 5 member ring. The takeaway point is that although ring-strain (having non ideal angles (120 or 109.5 degrees)) increases the internal energy of the molecule (destabilizing it), other factors, such as aromaticity, which decrease internal energy (stabilizing it) may balance or exceed the ring-strain, still giving a stabilized, if non-ideal geometry. (But yeah, 3, 4 membered rings, ugh. Look up platonic alkanes for some really crazy strain angles.)
- RDeckard 13y agoAre you a chemist?
- deleted 13y ago[deleted]