page_title: Bicyclic molecule
hierarchical_section_title: Bicyclic molecule
caption_attribution_description: Ball-and-stick model of the Spiro[5.5]undecane molecule, an example of a spiro compound, with two rings connected through just one atom. Colour code: &#x2002; Carbon, C: black &#x2002; Hydrogen, H: white
context_page_description: A bicyclic molecule is a molecule that features two joined rings. Bicyclic structures occur widely, for example in many biologically important molecules like α-thujene and camphor. A bicyclic compound can be carbocyclic, or heterocyclic, like DABCO. Moreover, the two rings can both be aliphatic, or can be aromatic, or a combination of aliphatic and aromatic.
  Three modes of ring junction are possible for a bicyclic compound:
  In spirocyclic compounds, the two rings share only one single atom, the spiro atom, which is usually a quaternary carbon. An example of a spirocyclic compound is the photochromic switch spiropyran.
  In fused bicyclic compounds, two rings share two adjacent atoms. In other words, the rings share one covalent bond, i.e. the so-called bridgehead atoms are directly connected.
  In bridged bicyclic compounds, the two rings share three or more atoms, separating the two bridgehead atoms by a bridge containing at least one atom. For example, norbornane, also known as bicyclo[2.2.1]heptane, can be viewed as a pair of cyclopentane rings each sharing three of their five carbon atoms. Camphor is a more elaborate example.
context_section_description: A bicyclic molecule (bi = two, cycle = ring) is a molecule that features two joined rings. Bicyclic structures occur widely, for example in many biologically important molecules like α-thujene and camphor. A bicyclic compound can be carbocyclic (all of the ring atoms are carbons), or heterocyclic (the rings atoms consist of at least two elements), like DABCO. Moreover, the two rings can both be aliphatic (e.g. decalin and norbornane), or can be aromatic (e.g. naphthalene), or a combination of aliphatic and aromatic (e.g. tetralin).
  Three modes of ring junction are possible for a bicyclic compound:
  In spirocyclic compounds, the two rings share only one single atom, the spiro atom, which is usually a quaternary carbon. An example of a spirocyclic compound is the photochromic switch spiropyran.
  In fused bicyclic compounds, two rings share two adjacent atoms. In other words, the rings share one covalent bond, i.e. the so-called bridgehead atoms are directly connected (e.g. α-thujene  and decalin).
  In bridged bicyclic compounds, the two rings share three or more atoms, separating the two bridgehead atoms by a bridge containing at least one atom. For example, norbornane, also known as bicyclo[2.2.1]heptane, can be viewed as a pair of cyclopentane rings each sharing three of their five carbon atoms. Camphor is a more elaborate example.
caption: The spirocyclic compound spiro[5.5]undecane.
exif: {}